Various fixes to ipapp/ipcluster/ipengine/ipcontroller. * Fixed bugs in handling of ``reuse_furls`` and ``secure``. * Fixed ``--no-sep`` option. * Refactored how the :attr:`Application.config_file_name` is handled to make it clearer and more robust. * Tested all the apps.

Reverted decorators_trial.py and added command line docs. * Reverted :mod:`IPython.testing.decorators_trial.py` and everything that uses it. * Updated the command line usage information for ipcluster.

More work to address review comments. * Moved twisted import to top-level of :mod:`IPython.kernel.error` (r1333). * Added docstring about :meth:`InteractiveShell.load_extension` returning whatever the return value of :func:`load_ipython_extension` is. * Renamed the :attr:`user_config_ns` attribute to :attr:`user_ns_hidden` to better reflect what it does. * Moved the ``%HOME`` to the end of home directory options attemped in :func:`IPython.utils.path.get_home_dir` on Windows.

Reenabled the test test_asyncfrontendbase.py. For some reason this was being skipped by nose. Re-enabled and all tests pass.

Removed the top-level iptest.py and INSTALLED logic. Fernando's branch introduced the ability to run the test suite from a top-level iptest.py script. This allowed IPython to be tested without installation. The implementation was fragile and we also decided that we *want* people to install IPython as part of testing it, so we removed this feature.

More work on the crash handler. * Made a subclass of :class:`IPython.core.crashhandler.CrashHandler` for each application we have. Each of these has a custom message and uses the name and email of the appropriate personf for that app. * Removed the :meth:`IPython.core.application.abort` method. * Made small changes to how the crash handler is instantiated in :class:`IPython.core.application.Application`. * Tested the crash handlers.

Fixed broken test in :mod:`IPython.utils.tests.test_path`.

Fixed bug in ultratb.py and io.py. Previously :class:`IPython.utils.io.Term` had a :meth:`Term.writeln` method that :mod:`ultratb.py` was using. But, when a real stream or files is used in :class:`IPython.utils.io.Term` it doesn't have this method, so we were getting an error when the IPython Sphinx directive was run. I removed this method and made :mod:`ultratb.py` use just ``write``.

Fixed small bug in ipcluster. Some of the subparsers in ipcluster were not having the argument_default=SUPPRESS option passed to them so there were getting None as a default, which was overriding the config system defaults.

Removed IPython.config.default from the default search path for ipcluster When ipcluster searches for config files, it should not look in IPython.config.default because we ALWAYS move the default config files to cluster_dir (which is still on the search path).