Cleanup

- added imports from `__future__` to enforce python 3 style imports and unicode literals
    - removed `u''` style string literals (this makes the code python 3.2 compatible)
    - removed unused imports
    - fixed relative imports to use the `.` prefix
- added python 3.2 to travis testing
- added appropriate classifiers to `setup.py` for tested versions of python
- added `django` and `babel` to install requirements in `setup.py`