Added a testing harness and two test cases.

First time testing django management commands. It was a little trickier than I expected.

I followed these sources:

http://stackoverflow.com/questions/6164004/python-package-structure-setup-py-for-running-unit-tests
http://stackoverflow.com/questions/1286700/how-to-test-custom-django-admin-commands

The tests come from

https://github.com/jessemiller/HamlPy