Python 3 support

[techtonik]

Reticketed from #10, because I am not able to contact people from Google Code. If you're about to submit pull request, make sure to uncomment Python 3 lines in https://github.com/techtonik/python-patch/blob/master/.travis.yml

Where is this needed:

• Patch is not available for Python 3 on Windows conda/conda-build#498
• patch error with skeleton pypi on Windows 7 64-bit conda/conda-build#119