Got tests passing in Django 1.4 - 1.7, python 2.7, 3.3, 3.4, and pypy; added classifiers

- Travis tests now run (and pass) for Django 1.4 - 1.7 (dropped 1.3 as it is no longer supported)
- Travis tests now run (and pass) using Python 2.7, 3.3, 3.4, and pypy (dropped 2.6)
- added PyPI classifiers for all tested versions of python
- changed the deprecated `User.get_profile()` pattern to a `OneToOneField` relation
- changed the deprecated `assertEquals` method to `assertEqual`