Log Message:
Update to 0.8:

0.8.0 (2014-03-22):
  - Adapt for the AST in Python 3.4.
  - Fix caret position on SyntaxError.
  - Fix crash on Python 2.x with some doctest SyntaxError.
  - Add tox.ini.
  - The `PYFLAKES_NODOCTEST` environment variable has been replaced with the
    `PYFLAKES_DOCTEST` environment variable (with the opposite meaning).
    Doctest checking is now disabled by default; set the environment variable
    to enable it.
  - Correctly parse incremental `__all__ += [...]`.
  - Catch return with arguments inside a generator (Python <= 3.2).
  - Do not complain about `_` in doctests.
  - Drop deprecated methods `pushFunctionScope` and `pushClassScope`.