Switch master to development of 6.0

I'm thinking about this because we've just released 5.1, but I'm happy
for it to wait a bit longer if we prefer. As planned, 6.0 will require
Python 3, while we will continue to support 5.x for some time for Python
2 users.

Before merging this, we should send a message to the mailing list for
any Python 2 users following master, and make a 5.x branch off master.

.travis.yml

@@ -1,44 +1,25 b''
 # http://travis-ci.org/#!/ipython/ipython
 language: python
 python:
     - "nightly"
     - 3.5
     - 3.4
     - 3.3
-    - 2.7
-    - pypy
 sudo: false
 before_install:
     - git clone --quiet --depth 1 https://github.com/minrk/travis-wheels travis-wheels
     - 'if [[ $GROUP != js* ]]; then COVERAGE=""; fi'
 install:
     - pip install "setuptools>=18.5"
-    # Installs PyPy (+ its Numpy). Based on @frol comment at:
-    # https://github.com/travis-ci/travis-ci/issues/5027
-    - |
-        if [ "$TRAVIS_PYTHON_VERSION" = "pypy" ]; then
-          export PYENV_ROOT="$HOME/.pyenv"
-          if [ -f "$PYENV_ROOT/bin/pyenv" ]; then
-            cd "$PYENV_ROOT" && git pull
-          else
-            rm -rf "$PYENV_ROOT" && git clone --depth 1 https://github.com/yyuu/pyenv.git "$PYENV_ROOT"
-          fi
-          export PYPY_VERSION="5.3.1"
-          "$PYENV_ROOT/bin/pyenv" install "pypy-$PYPY_VERSION"
-          virtualenv --python="$PYENV_ROOT/versions/pypy-$PYPY_VERSION/bin/python" "$HOME/virtualenvs/pypy-$PYPY_VERSION"
-          source "$HOME/virtualenvs/pypy-$PYPY_VERSION/bin/activate"
-          pip install https://bitbucket.org/pypy/numpy/get/master.zip
-        fi
     - pip install -f travis-wheels/wheelhouse -e file://$PWD#egg=ipython[test]
     - pip install codecov
 script:
     - cd /tmp && iptest --coverage xml && cd -
 after_success:
     - cp /tmp/ipy_coverage.xml ./
     - cp /tmp/.coverage ./
     - codecov
 
 matrix:
     allow_failures:
         - python: nightly
-        - python: pypy

IPython/core/release.py

@@ -1,123 +1,121 b''
 # -*- coding: utf-8 -*-
 """Release data for the IPython project."""
 
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2008, IPython Development Team.
 #  Copyright (c) 2001, Fernando Perez <[e-mail]>
 #  Copyright (c) 2001, Janko Hauser <[e-mail]>
 #  Copyright (c) 2001, Nathaniel Gray <[e-mail]>
 #
 #  Distributed under the terms of the Modified BSD License.
 #
 #  The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 # Name of the package for release purposes.  This is the name which labels
 # the tarballs and RPMs made by distutils, so it's best to lowercase it.
 name = 'ipython'
 
 # IPython version information.  An empty _version_extra corresponds to a full
 # release.  'dev' as a _version_extra string means this is a development
 # version
-_version_major = 5
-_version_minor = 2
+_version_major = 6
+_version_minor = 0
 _version_patch = 0
 _version_extra = '.dev'
 # _version_extra = 'rc1'
 # _version_extra = ''  # Uncomment this for full releases
 
 # release.codename is deprecated in 2.0, will be removed in 3.0
 codename = ''
 
 # Construct full version string from these.
 _ver = [_version_major, _version_minor, _version_patch]
 
 __version__ = '.'.join(map(str, _ver))
 if _version_extra:
     __version__ = __version__  + _version_extra
 
 version = __version__  # backwards compatibility name
 version_info = (_version_major, _version_minor, _version_patch, _version_extra)
 
 # Change this when incrementing the kernel protocol version
 kernel_protocol_version_info = (5, 0)
 kernel_protocol_version = "%i.%i" % kernel_protocol_version_info
 
 description = "IPython: Productive Interactive Computing"
 
 long_description = \
 """
 IPython provides a rich toolkit to help you make the most out of using Python
 interactively.  Its main components are:
 
 * A powerful interactive Python shell
 * A `Jupyter <http://jupyter.org/>`_ kernel to work with Python code in Jupyter
   notebooks and other interactive frontends.
 
 The enhanced interactive Python shells have the following main features:
 
 * Comprehensive object introspection.
 
 * Input history, persistent across sessions.
 
 * Caching of output results during a session with automatically generated
   references.
 
 * Extensible tab completion, with support by default for completion of python
   variables and keywords, filenames and function keywords.
 
 * Extensible system of 'magic' commands for controlling the environment and
   performing many tasks related either to IPython or the operating system.
 
 * A rich configuration system with easy switching between different setups
   (simpler than changing $PYTHONSTARTUP environment variables every time).
 
 * Session logging and reloading.
 
 * Extensible syntax processing for special purpose situations.
 
 * Access to the system shell with user-extensible alias system.
 
 * Easily embeddable in other Python programs and GUIs.
 
 * Integrated access to the pdb debugger and the Python profiler.
 
 The latest development version is always available from IPython's `GitHub
 site <http://github.com/ipython>`_.
 """
 
 license = 'BSD'
 
 authors = {'Fernando' : ('Fernando Perez','[e-mail]'),
            'Janko'    : ('Janko Hauser','[e-mail]'),
            'Nathan'   : ('Nathaniel Gray','[e-mail]'),
            'Ville'    : ('Ville Vainio','[e-mail]'),
            'Brian'    : ('Brian E Granger', '[e-mail]'),
            'Min'      : ('Min Ragan-Kelley', '[e-mail]'),
            'Thomas'   : ('Thomas A. Kluyver', '[e-mail]'),
            'Jorgen'   : ('Jorgen Stenarson', '[e-mail]'),
            'Matthias' : ('Matthias Bussonnier', '[e-mail]'),
            }
 
 author = 'The IPython Development Team'
 
 author_email = '[e-mail]'
 
 url = 'http://ipython.org'
 
 
 platforms = ['Linux','Mac OSX','Windows']
 
 keywords = ['Interactive','Interpreter','Shell', 'Embedding']
 
 classifiers = [
     'Framework :: IPython',
     'Intended Audience :: Developers',
     'Intended Audience :: Science/Research',
     'License :: OSI Approved :: BSD License',
     'Programming Language :: Python',
-    'Programming Language :: Python :: 2',
-    'Programming Language :: Python :: 2.7',
     'Programming Language :: Python :: 3',
     'Topic :: System :: Shells'
     ]