Pyflakes

- Add --version and --help options.
- Support ``python -m pyflakes`` (Python 2.7 and Python 3.x).
- Add attribute ``Message.col`` to report column offset.
- Do not report redefinition of variable for a variable used in a list
comprehension in a conditional.
- Do not report redefinition of variable for generator expressions and
set or dict comprehensions.
- Do not report undefined name when the code is protected with a
``NameError`` exception handler.
- Do not report redefinition of variable when unassigning a module imported
for its side-effect.
- Support special locals like ``__tracebackhide__`` for py.test.
- Support checking doctests.
- Fix issue with Turkish locale where ``'i'.upper() == 'i'`` in Python 2.

- Fix detection of variables in augmented assignments.

- Support Python 3 up to 3.3, based on the pyflakes3k project.
- Preserve compatibility with Python 2.5 and all recent versions of Python.
- Support custom reporters in addition to the default Reporter.
- Allow function redefinition for modern property construction via
property.setter/deleter.
- Fix spurious redefinition warnings in conditionals.
- Do not report undefined name in ``__all__`` if import * is used.
- Add WindowsError as a known built-in name on all platforms.
- Support specifying additional built-ins in the ``Checker`` constructor.
- Don't issue Unused Variable warning when using locals() in current scope.
- Handle problems with the encoding of source files.
- Remove dependency on Twisted for the tests.
- Support ``python setup.py test`` and ``python setup.py develop``.
- Create script using setuptools ``entry_points`` to support all platforms,
including Windows.

- Convert pyflakes to use newer _ast infrastructure rather than compiler.
- Support for new syntax in 2.7 (including set literals, set comprehensions,
and dictionary comprehensions).
- Make sure class names don't get bound until after class definition.

- Fix reporting for certain SyntaxErrors which lack line number
information.
- Check for syntax errors more rigorously.
- Support checking names used with the class decorator syntax in versions
of Python which have it.
- Detect local variables which are bound but never used.
- Handle permission errors when trying to read source files.
- Handle problems with the encoding of source files.
- Support importing dotted names so as not to incorrectly report them as
redefined unused names.
- Support all forms of the with statement.
- Consider static ``__all__`` definitions and avoid reporting unused names
if the names are listed there.
- Fix incorrect checking of class names with respect to the names of their
bases in the class statement.
- Support the ``__path__`` global in ``__init__.py``.

- Display more informative SyntaxError messages.
- Don't hang flymake with unmatched triple quotes (only report a single
line of source for a multiline syntax error).
- Recognize ``__builtins__`` as a defined name.
- Improve pyflakes support for python versions 2.3-2.5
- Support for if-else expressions and with statements.
- Warn instead of error on non-existent file paths.
- Check for ``__future__`` imports after other statements.
- Add reporting for some types of import shadowing.
- Improve reporting of unbound locals