date typos

docs/source/whatsnew/version2.0.rst

@@ -1,379 +1,379 b''
 ============
  2.x Series
 ============
 
 Release 2.4
 ===========
 
-January, 2014
+January, 2015
 
 - backport read support for nbformat v4 from IPython 3
 - support for PyQt5
 - support for Pygments 2.0
 
 For more information on what fixes have been backported to 2.4,
 see our :ref:`detailed release info <issues_list_200>`.
 
 
 Release 2.3.1
 =============
 
 November, 2014
 
 - Fix CRCRLF line-ending bug in notebooks on Windows
 
 For more information on what fixes have been backported to 2.3.1,
 see our :ref:`detailed release info <issues_list_200>`.
 
 Release 2.3.0
 =============
 
 October, 2014
 
 - improve qt5 support
 - prevent notebook data loss with atomic writes
 
 For more information on what fixes have been backported to 2.3,
 see our :ref:`detailed release info <issues_list_200>`.
 
 Release 2.2.0
 =============
 
 August, 2014
 
 - Add CORS configuration
 
 For more information on what fixes have been backported to 2.2,
 see our :ref:`detailed release info <issues_list_200>`.
 
 Release 2.1.0
 =============
 
 May, 2014
 
 IPython 2.1 is the first bugfix release for 2.0.
 For more information on what fixes have been backported to 2.1,
 see our :ref:`detailed release info
 <issues_list_200>`.
 
 
 Release 2.0.0
 =============
 
 April, 2014
 
 IPython 2.0 requires Python ≥ 2.7.2 or ≥ 3.3.0.
 It does not support Python 3.0, 3.1, 3.2, 2.5, or 2.6.
 
 The principal milestones of 2.0 are:
 
 - interactive widgets for the notebook
 - directory navigation in the notebook dashboard
 - persistent URLs for notebooks
 - a new modal user interface in the notebook
 - a security model for notebooks
 
 Contribution summary since IPython 1.0 in August, 2013:
 
 - ~8 months of work
 - ~650 pull requests merged
 - ~400 issues closed (non-pull requests)
 - contributions from ~100 authors
 - ~4000 commits
 
 The amount of work included in this release is so large that we can only cover
 here the main highlights; please see our :ref:`detailed release statistics
 <issues_list_200>` for links to every issue and pull request closed on GitHub
 as well as a full list of individual contributors.
 
 New stuff in the IPython notebook
 ---------------------------------
 
 Directory navigation
 ********************
 
 .. image:: /_images/2.0/treeview.png
     :width: 392px
     :alt: Directory navigation
     :align: center
 
 The IPython notebook dashboard allows navigation into subdirectories.
 URLs are persistent based on the notebook's path and name,
 so no more random UUID URLs.
 
 Serving local files no longer needs the ``files/`` prefix.
 Relative links across notebooks and other files should work just as if notebooks were regular HTML files.
 
 Interactive widgets
 *******************
 
 .. image:: /_images/2.0/widgets.png
     :width: 392px
     :alt: Interactive widgets
     :align: center
 
 IPython 2.0 adds :mod:`IPython.html.widgets`, for manipulating
 Python objects in the kernel with GUI controls in the notebook.
 IPython comes with a few built-in widgets for simple data types,
 and an API designed for developers to build more complex widgets.
 See the `widget docs`_ for more information.
 
 .. _widget docs: http://nbviewer.ipython.org/github/ipython/ipython/blob/2.x/examples/Interactive%20Widgets/Index.ipynb
 
 
 Modal user interface
 ********************
 
 The notebook has added separate Edit and Command modes,
 allowing easier keyboard commands and making keyboard shortcut customization possible.
 See the new `User Interface notebook`_ for more information.
 
 .. _User Interface Notebook: http://nbviewer.ipython.org/github/ipython/ipython/blob/2.x/examples/Notebook/User%20Interface.ipynb
 
 
 You can familiarize yourself with the updated notebook user interface, including an
 explanation of Edit and Command modes, by going through the short guided tour
 which can be started from the Help menu.
 
 .. image:: /_images/2.0/user-interface.png
     :width: 392px
     :alt: Interface tour
     :align: center
 
 
 Security
 ********
 
 2.0 introduces a :ref:`security model <notebook_security>` for notebooks,
 to prevent untrusted code from executing on users' behalf when notebooks open.
 A quick summary of the model:
 
 - Trust is determined by :ref:`signing notebooks<signing_notebooks>`.
 - Untrusted HTML output is sanitized.
 - Untrusted Javascript is never executed.
 - HTML and Javascript in Markdown are never trusted.
 
 Dashboard "Running" tab
 ***********************
 
 .. image:: /_images/2.0/running-crop.png
     :width: 392px
     :alt: Running tab
     :align: center
 
 The dashboard now has a "Running" tab which shows all of the running notebooks.
 
 Single codebase Python 3 support
 --------------------------------
 
 IPython previously supported Python 3 by running 2to3 during setup. We
 have now switched to a single codebase which runs natively on Python 2.7
 and 3.3.
 
 For notes on how to maintain this, see :doc:`/development/pycompat`.
 
 Selecting matplotlib figure formats
 -----------------------------------
 
 Deprecate single-format ``InlineBackend.figure_format``
 configurable in favor of ``InlineBackend.figure_formats``,
 which is a set, supporting multiple simultaneous figure formats (e.g. png, pdf).
 
 This is available at runtime with the new API function :func:`IPython.display.set_matplotlib_formats`.
 
 clear_output changes
 --------------------
 
 * There is no longer a 500ms delay when calling ``clear_output``.
 * The ability to clear stderr and stdout individually was removed.
 * A new ``wait`` flag that prevents ``clear_output`` from being executed until new
   output is available.  This eliminates animation flickering by allowing the
   user to double buffer the output.
 * The output div height is remembered when the ``wait=True`` flag is used.
 
 Extending configurable containers
 ---------------------------------
 
 Some configurable traits are containers (list, dict, set)
 Config objects now support calling ``extend``, ``update``, ``insert``, etc.
 on traits in config files, which will ultimately result in calling
 those methods on the original object.
 
 The effect being that you can now add to containers without having to copy/paste
 the initial value::
 
     c = get_config()
     c.InlineBackend.rc.update({ 'figure.figsize' : (6, 4) })
 
 Changes to hidden namespace on startup
 --------------------------------------
 
 Previously, all names declared in code run at startup
 (startup files, ``ipython -i script.py``, etc.)
 were added to the hidden namespace, which hides the names from tools like ``%whos``.
 There are two changes to this behavior:
 
 1. Scripts run on the command-line ``ipython -i script.py``now behave the same as if they were
    passed to ``%run``, so their variables are never hidden.
 2. A boolean config flag ``InteractiveShellApp.hide_initial_ns`` has been added to optionally
    disable the hidden behavior altogether. The default behavior is unchanged.
 
 Using dill to expand serialization support
 ------------------------------------------
 
 The new function :func:`~IPython.utils.pickleutil.use_dill` allows
 dill to extend serialization support in :mod:`IPython.parallel` (closures, etc.).
 A :meth:`DirectView.use_dill` convenience method was also added, to enable dill
 locally and on all engines with one call.
 
 New IPython console lexer
 -------------------------
 
 The IPython console lexer has been rewritten and now supports tracebacks
 and customized input/output prompts. See the :ref:`new lexer docs <console_lexer>`
 for details.
 
 DisplayFormatter changes
 ------------------------
 
 There was no official way to query or remove callbacks in the Formatter API.
 To remedy this, the following methods are added to :class:`BaseFormatter`:
 
 - ``lookup(instance)`` - return appropriate callback or a given object
 - ``lookup_by_type(type_or_str)`` - return appropriate callback for a given type or ``'mod.name'`` type string
 - ``pop(type_or_str)`` - remove a type (by type or string).
   Pass a second argument to avoid KeyError (like dict).
 
 All of the above methods raise a KeyError if no match is found.
 
 And the following methods are changed:
 
 - ``for_type(type_or_str)`` - behaves the same as before, only adding support for ``'mod.name'``
   type strings in addition to plain types. This removes the need for ``for_type_by_name()``,
   but it remains for backward compatibility.
 
 Formatters can now raise NotImplementedError in addition to returning None
 to indicate that they cannot format a given object.
 
 Exceptions and Warnings
 ***********************
 
 Exceptions are no longer silenced when formatters fail.
 Instead, these are turned into a :class:`~IPython.core.formatters.FormatterWarning`.
 A FormatterWarning will also be issued if a formatter returns data of an invalid type
 (e.g. an integer for 'image/png').
 
 
 Other changes
 -------------
 
 * `%%capture` cell magic now captures the rich display output, not just
   stdout/stderr
 
 * In notebook, Showing tooltip on tab has been disables to avoid conflict with
   completion, Shift-Tab could still be used to invoke tooltip when inside
   function signature and/or on selection.
 
 * ``object_info_request`` has been replaced by ``object_info`` for consistency in the javascript API.
   ``object_info`` is a simpler interface to register callback that is incompatible with ``object_info_request``.
 
 * Previous versions of IPython on Linux would use the XDG config directory,
   creating :file:`~/.config/ipython` by default. We have decided to go
   back to :file:`~/.ipython` for consistency among systems. IPython will
   issue a warning if it finds the XDG location, and will move it to the new
   location if there isn't already a directory there.
 
 * Equations, images and tables are now centered in Markdown cells.
 * Multiline equations are now centered in output areas; single line equations
   remain left justified.
 
 * IPython config objects can be loaded from and serialized to JSON.
   JSON config file have the same base name as their ``.py`` counterpart,
   and will be loaded with higher priority if found.
 
 * bash completion updated with support for all ipython subcommands and flags, including nbconvert
 
 * ``ipython history trim``: added ``--keep=<N>`` as an alias for the more verbose
   ``--HistoryTrim.keep=<N>``
 * New ``ipython history clear`` subcommand, which is the same as the newly supported
   ``ipython history trim --keep=0``
 
 * You can now run notebooks in an interactive session via ``%run notebook.ipynb``.
 
 * Print preview is back in the notebook menus, along with options to
   download the open notebook in various formats. This is powered by
   nbconvert.
 
 * :exc:`~IPython.nbconvert.utils.pandoc.PandocMissing` exceptions will be
   raised if Pandoc is unavailable, and warnings will be printed if the version
   found is too old. The recommended Pandoc version for use with nbconvert is
   1.12.1.
 
 * The InlineBackend.figure_format now supports JPEG output if PIL/Pillow is available.
 
 * Input transformers (see :doc:`/config/inputtransforms`) may now raise
   :exc:`SyntaxError` if they determine that input is invalid. The input
   transformation machinery in IPython will handle displaying the exception to
   the user and resetting state.
 
 * Calling ``container.show()`` on javascript display is deprecated and will
   trigger errors on future IPython notebook versions. ``container`` now show
   itself as soon as non-empty
 
 * Added ``InlineBackend.print_figure_kwargs`` to allow passing keyword arguments
   to matplotlib's ``Canvas.print_figure``. This can be used to change the value of
   ``bbox_inches``, which is 'tight' by default, or set the quality of JPEG figures.
 
 * A new callback system has been introduced. For details, see :doc:`/config/callbacks`.
 
 * jQuery and require.js are loaded from CDNs in the default HTML template,
   so javascript is available in static HTML export (e.g. nbviewer).
 
 Backwards incompatible changes
 ------------------------------
 
 * Python 2.6 and 3.2 are no longer supported: the minimum required
   Python versions are now 2.7 and 3.3.
 * The Transformer classes have been renamed to Preprocessor in nbconvert and
   their ``call`` methods have been renamed to ``preprocess``.
 * The ``call`` methods of nbconvert post-processsors have been renamed to
   ``postprocess``.
 
 * The module ``IPython.core.fakemodule`` has been removed.
 
 * The alias system has been reimplemented to use magic functions. There should be little
   visible difference while automagics are enabled, as they are by default, but parts of the
   :class:`~IPython.core.alias.AliasManager` API have been removed.
 
 * We fixed an issue with switching between matplotlib inline and GUI backends,
   but the fix requires matplotlib 1.1 or newer.  So from now on, we consider
   matplotlib 1.1 to be the minimally supported version for IPython. Older
   versions for the most part will work, but we make no guarantees about it.
 
 * The :command:`pycolor` command has been removed. We recommend the much more capable
   :command:`pygmentize` command from the `Pygments <http://pygments.org/>`_ project.
   If you need to keep the exact output of :command:`pycolor`, you can still use
   ``python -m IPython.utils.PyColorize foo.py``.
 
 * :mod:`IPython.lib.irunner` and its command-line entry point have been removed.
   It had fallen out of use long ago.
 
 * The ``input_prefilter`` hook has been removed, as it was never
   actually used by the code. The input transformer system offers much
   more powerful APIs to work with input code. See
   :doc:`/config/inputtransforms` for details.
 
 * :class:`IPython.core.inputsplitter.IPythonInputSplitter` no longer has a method
   ``source_raw_reset()``, but gains :meth:`~IPython.core.inputsplitter.IPythonInputSplitter.raw_reset`
   instead. Use of ``source_raw_reset`` can be replaced with::
 
       raw = isp.source_raw
       transformed = isp.source_reset()
 
 * The Azure notebook manager was removed as it was no longer compatible with the notebook storage scheme.
 
 * Simplifying configurable URLs
 
   - base_project_url is renamed to base_url (base_project_url is kept as a deprecated alias, for now)
   - base_kernel_url configurable is removed (use base_url)
   - websocket_url configurable is removed (use base_url)

docs/source/whatsnew/version3.rst

@@ -1,310 +1,310 b''
 ============
  3.x Series
 ============
 
 
 Release 3.0
 ===========
 
-Coming Feburary, 2015
+Coming February, 2015
 
 This is a really big release. Over 150 contributors, and almost 6000 commits in a bit under a year.
 Support for languages other than Python is greatly improved,
 notebook UI has been significantly redesigned,
 and a lot of improvement has happened in the experimental interactive widgets.
 The message protocol and document format have both been updated,
 while maintaining better compatibility with previous versions than prior updates.
 The notebook webapp now enables editing of any text file, and even
 a web-based terminal (on Unix platforms).
 
 3.x will be the last monolithic release of IPython,
 as the next release cycle will see the growing project split into its Python-specific and language-agnostic components.
 Language-agnostic projects (notebook, qtconsole, etc.) will move under the umbrella of the new Project Jupyter name,
 while Python-specific projects (interactive Python shell, Python kernel, IPython.parallel)
 will remain under IPython, and be split into a few smaller packages.
 To reflect this, IPython is in a bit of a transition state.
 The logo on the notebook is now the Jupyter logo.
 When installing kernels system-wide, they go in a `jupyter` directory.
 We are going to do our best to ease this transition for users and developers.
 
 Big changes are ahead.
 
 
 Using different kernels
 -----------------------
 
 .. image:: ../_images/kernel_selector_screenshot.png
    :alt: Screenshot of 'new' dropdown showing different kernels
    :align: center
 
 You can now choose a kernel for a notebook within the user interface, rather
 than starting up a separate notebook server for each kernel you want to use. The
 syntax highlighting adapts to match the language you're working in.
 
 Information about the kernel is stored in the notebook file, so when you open a
 notebook, it will automatically start the correct kernel.
 
 It is also easier to use the Qt console and the terminal console with other
 kernels, using the --kernel flag::
 
     ipython qtconsole --kernel bash
     ipython console --kernel bash
 
     # To list available kernels
     ipython kernelspec list
 
 Kernel authors should see :ref:`kernelspecs` for how to register their kernels
 with IPython so that these mechanisms work.
 
 Typing unicode identifiers
 --------------------------
 
 .. image:: /_images/unicode_completion.png
 
 Complex expressions can be much cleaner when written with a wider choice of
 characters. Python 3 allows unicode identifiers, and IPython 3 makes it easier
 to type those, using a feature from Julia. Type a backslash followed by a LaTeX
 style short name, such as ``\alpha``. Press tab, and it will turn into α.
 
 Other new features
 ------------------
 
 * :class:`~.TextWidget` and :class:`~.TextareaWidget` objects now include a
   ``placeholder`` attribute, for displaying placeholder text before the
   user has typed anything.
 
 * The :magic:`load` magic can now find the source for objects in the user namespace.
   To enable searching the namespace, use the ``-n`` option.
 
   .. sourcecode:: ipython
 
       In [1]: %load -n my_module.some_function
 
 * :class:`~.DirectView` objects have a new :meth:`~.DirectView.use_cloudpickle`
   method, which works like ``view.use_dill()``, but causes the ``cloudpickle``
   module from PiCloud's `cloud`__ library to be used rather than dill or the
   builtin pickle module.
 
   __ https://pypi.python.org/pypi/cloud
 
 * Added a .ipynb exporter to nbconvert.  It can be used by passing `--to notebook`
   as a commandline argument to nbconvert.
 
 * New nbconvert preprocessor called :class:`~.ClearOutputPreprocessor`. This
   clears the output from IPython notebooks.
 
 * New preprocessor for nbconvert that executes all the code cells in a notebook.
   To run a notebook and save its output in a new notebook::
 
       ipython nbconvert InputNotebook --ExecutePreprocessor.enabled=True --to notebook --output Executed
 
 * Consecutive stream (stdout/stderr) output is merged into a single output
   in the notebook document.
   Previously, all output messages were preserved as separate output fields in the JSON.
   Now, the same merge is applied to the stored output as the displayed output,
   improving document load time for notebooks with many small outputs.
 
 * ``NotebookApp.webapp_settings`` is deprecated and replaced with
   the more informatively named ``NotebookApp.tornado_settings``.
 
 * Using :magic:`timeit` prints warnings if there is atleast a 4x difference in timings
   between the slowest and fastest runs, since this might meant that the multiple
   runs are not independent of one another.
 
 * It's now possible to provide mechanisms to integrate IPython with other event
   loops, in addition to the ones we already support. This lets you run GUI code
   in IPython with an interactive prompt, and to embed the IPython
   kernel in GUI applications. See :doc:`/config/eventloops` for details. As part
   of this, the direct ``enable_*`` and ``disable_*`` functions for various GUIs
   in :mod:`IPython.lib.inputhook` have been deprecated in favour of
   :meth:`~.InputHookManager.enable_gui` and :meth:`~.InputHookManager.disable_gui`.
 
 * A ``ScrollManager`` was added to the notebook.  The ``ScrollManager`` controls how the notebook document is scrolled using keyboard.  Users can inherit from the ``ScrollManager`` or ``TargetScrollManager`` to customize how their notebook scrolls.  The default ``ScrollManager`` is the ``SlideScrollManager``, which tries to scroll to the nearest slide or sub-slide cell.
 
 * The function :func:`~IPython.html.widgets.interaction.interact_manual` has been
   added which behaves similarly to :func:`~IPython.html.widgets.interaction.interact`,
   but adds a button to explicitly run the interacted-with function, rather than
   doing it automatically for every change of the parameter widgets. This should
   be useful for long-running functions.
 
 * The ``%cython`` magic is now part of the Cython module. Use `%load_ext Cython` with a version of Cython >= 0.21 to have access to the magic now.
 
 * The Notebook application now offers integrated terminals on Unix platforms,
   intended for when it is used on a remote server. To enable these, install
   the ``terminado`` Python package.
 
 * The Notebook application can now edit any plain text files, via a full-page CodeMirror instance.
 
 * Setting the default highlighting language for nbconvert with the config option
   ``NbConvertBase.default_language`` is deprecated. Nbconvert now respects
   metadata stored in the :ref:`kernel spec <kernelspecs>`.
 
 * IPython can now be configured systemwide, with files in :file:`/etc/ipython`
   or :file:`/usr/local/etc/ipython` on Unix systems,
   or :file:`{%PROGRAMDATA%}\\ipython` on Windows.
 
 * Added support for configurable user-supplied `Jinja
   <http://jinja.pocoo.org/>`_ HTML templates for the notebook.  Paths to
   directories containing template files can be specified via
   ``NotebookApp.extra_template_paths``.  User-supplied template directories
   searched first by the notebook, making it possible to replace existing
   templates with your own files.
 
   For example, to replace the notebook's built-in ``error.html`` with your own,
   create a directory like ``/home/my_templates`` and put your override template
   at ``/home/my_templates/error.html``.  To start the notebook with your custom
   error page enabled, you would run::
 
       ipython notebook '--extra_template_paths=["/home/my_templates/"]'
 
   It's also possible to override a template while also `inheriting
   <http://jinja.pocoo.org/docs/dev/templates/#template-inheritance>`_ from that
   template, by prepending ``templates/`` to the ``{% extends %}`` target of
   your child template.  This is useful when you only want to override a
   specific block of a template.  For example, to add additional CSS to the
   built-in ``error.html``, you might create an override that looks like::
 
     {% extends "templates/error.html" %}
 
     {% block stylesheet %}
     {{super()}}
     <style type="text/css">
       /* My Awesome CSS */
     </style>
     {% endblock %}
 
 * Added a widget persistence API.  This allows you to persist your notebooks interactive widgets.
   Two levels of control are provided:
   1. Higher level- ``WidgetManager.set_state_callbacks`` allows you to register callbacks for loading and saving widget state.  The callbacks you register are automatically called when necessary.
   2. Lower level- the ``WidgetManager`` Javascript class now has ``get_state`` and ``set_state`` methods that allow you to get and set the state of the widget runtime.
 
   Example code for persisting your widget state to session data::
 
     %%javascript
     require(['widgets/js/manager'], function(manager) {
         manager.WidgetManager.set_state_callbacks(function() { // Load
             return JSON.parse(sessionStorage.widgets_state || '{}');
         }, function(state) { // Save
             sessionStorage.widgets_state = JSON.stringify(state);
         });
     });
 
 * Enhanced support for :magic:`env` magic.  As before, :magic:`env` with no
   arguments displays all environment variables and values.  Additionally,
   :magic:`env` can be used to get or set individual environment variables. To
   display an individual value, use the `%env var` syntax. To set a value, use
   `env var val` or `env var=val`. Python value expansion using `$` works as usual.
 
 
 Backwards incompatible changes
 ------------------------------
 
 * The :ref:`message protocol <messaging>` has been updated from version 4 to version 5.
   Adapters are included, so IPython frontends can still talk to kernels that
   implement protocol version 4.
 
 * The :ref:`notebook format <nbformat>` has been updated from version 3 to version 4.
   Read-only support for v4 notebooks has been backported to IPython 2.4.
   Notable changes:
   
   * heading cells are removed in favor or markdown headings
   * notebook outputs and output messages are more consistent with each other
   * use :func:`IPython.nbformat.read` and :func:`~IPython.nbformat.write`
     to read and write notebook files
     instead of the deprecated :mod:`IPython.nbformat.current` APIs.
 
 * :func:`IPython.core.oinspect.getsource` call specification has changed:
 
   * `oname` keyword argument has been added for property source formatting
   * `is_binary` keyword argument has been dropped, passing ``True`` had
     previously short-circuited the function to return ``None`` unconditionally
 
 * Removed the octavemagic extension: it is now available as ``oct2py.ipython``.
 
 * Creating PDFs with LaTeX no longer uses a post processor.
   Use `nbconvert --to pdf` instead of `nbconvert --to latex --post pdf`.
 
 * Used https://github.com/jdfreder/bootstrap2to3 to migrate the Notebook to Bootstrap 3.
 
   Additional changes:
 
   - Set `.tab-content .row` `0px;` left and right margin (bootstrap default is `-15px;`)
   - Removed `height: @btn_mini_height;` from `.list_header>div, .list_item>div` in `tree.less`
   - Set `#header` div `margin-bottom: 0px;`
   - Set `#menus` to `float: left;`
   - Set `#maintoolbar .navbar-text` to `float: none;`
   - Added no-padding convenience class.
   - Set border of #maintoolbar to 0px
 
 * Accessing the `container` DOM object when displaying javascript has been
   deprecated in IPython 2.0 in favor of accessing `element`. Starting with
   IPython 3.0 trying to access `container` will raise an error in browser
   javascript console.
 
 * ``IPython.utils.py3compat.open`` was removed: :func:`io.open` provides all
   the same functionality.
 
 * The NotebookManager and ``/api/notebooks`` service has been replaced by
   a more generic ContentsManager and ``/api/contents`` service,
   which supports all kinds of files.
 * The Dashboard now lists all files, not just notebooks and directories.
 * The ``--script`` hook for saving notebooks to Python scripts is removed,
   use :samp:`ipython nbconvert --to python {notebook}` instead.
 
 * The ``rmagic`` extension is deprecated, as it is now part of rpy2. See
   :mod:`rpy2.ipython.rmagic`.
 
 * :meth:`~.KernelManager.start_kernel` and :meth:`~.KernelManager.format_kernel_cmd`
   no longer accept a ``executable`` parameter. Use the kernelspec machinery instead.
 
 * The widget classes have been renamed from `*Widget` to `*`.  The old names are
   still functional, but are deprecated.  i.e. `IntSliderWidget` has been renamed
   to `IntSlider`.
 * The ContainerWidget was renamed to Box and no longer defaults as a flexible
   box in the web browser.  A new FlexBox widget was added, which allows you to
   use the flexible box model.
 
 * The notebook now uses a single websocket at `/kernels/<kernel-id>/channels` instead of separate
   `/kernels/<kernel-id>/{shell|iopub|stdin}` channels. Messages on each channel are identified by a
   `channel` key in the message dict, for both send and recv.
 
 
 Content Security Policy
 ```````````````````````
 
 The Content Security Policy is a web standard for adding a layer of security to
 detect and mitigate certain classes of attacks, including Cross Site Scripting
 (XSS) and data injection attacks. This was introduced into the notebook to
 ensure that the IPython Notebook and its APIs (by default) can only be embedded
 in an iframe on the same origin.
 
 Override ``headers['Content-Security-Policy']`` within your notebook
 configuration to extend for alternate domains and security settings.::
 
     c.NotebookApp.tornado_settings = {
         'headers': {
             'Content-Security-Policy': "frame-ancestors 'self'"
         }
     }
 
 Example policies::
 
     Content-Security-Policy: default-src 'self' https://*.jupyter.org
 
 Matches embeddings on any subdomain of jupyter.org, so long as they are served
 over SSL.
 
 There is a `report-uri <https://developer.mozilla.org/en-US/docs/Web/Security/CSP/CSP_policy_directives#report-uri>`_ endpoint available for logging CSP violations, located at
 ``/api/security/csp-report``. To use it, set ``report-uri`` as part of the CSP::
 
     c.NotebookApp.tornado_settings = {
         'headers': {
             'Content-Security-Policy': "frame-ancestors 'self'; report-uri /api/security/csp-report"
         }
     }
 
 It simply provides the CSP report as a warning in IPython's logs. The default
 CSP sets this report-uri relative to the ``base_url`` (not shown above).
 
 For a more thorough and accurate guide on Content Security Policies, check out
 `MDN's Using Content Security Policy <https://developer.mozilla.org/en-US/docs/Web/Security/CSP/Using_Content_Security_Policy>`_ for more examples.