Add support for Python 3 by doing 2to3 conversion on package install

According to http://python3porting.com/2to3.html#running-2to3-on-install this is an easy way to maintain compatibility for both Python 2.x and 3.x without requiring separate packages, separate source trees, or separate submissions.

I also fixed up setup.py so it was PEP8 compliant, added the appropriate trove classifier to indicate Python 3 support, and bumped the version number.