Tests pass under Django 1.5 / Python 3.3.

This probably means I broke some Python 2 stuff, however, so I wouldn't
call this "done" just yet.
Tox verifies this works with 2.6, 2.7, 3.3 and Django 1.4/1.5. Woot.
Added the various Py2/3 trove classifiers to setup.py.

Just showing off, really.
Merge pull request #13 from jacobian/master

Python 3 support