Added support for setup.cfg python-file-with-version option
Added tests for python file version setting detection
Looking at a __version__ attribute in a configured file, too
Added a `bin/python` script
Actually using __version__ ourselves
Documented the new __version__ behaviour
Use mode 'w' instead of 'wb' througout the code

File writes now use the platform's default line endings instead of always
writing ``\n`` unix style line endings. (Technically, we write using ``w``
instead of ``wb`` mode).
Merge pull request #39 from zestsoftware/reinout-version-attribute

zest.releaser can now also use a __version__ attribute in a configured Python file