Fixed testing, fixed python3 compatibility, added classifiers for PyPI

- Made it possible to run `python manage.py test` and get passing tests
- Added a `.travis.yml` file to enable Travis CI builds
- Fixed Python 3 compatibility without compromising Django 1.4 compatibility
- Added trove classifiers to `setup.py` for PyPI
That would cause Travis to test against Django 1.4.0, 1.5.0, 1.6.0, etc., instead of the most recent security releases (1.4.13, 1.5.8, 1.6.5, etc.).