Remove explicit Django requirement in preparation for Tox support
Add in support for detox to run tests in parallel
Update to use detox to run the tests
Remove Python 2.6 from TravisCI support

If someone wants to take this on, go for it, but 2.7 is pretty much the
standard at this point and the tests pass on TravisCI under 2.7 but have
issues with mail server mocking in 2.6.
Merge pull request #57 from tswicegood/add-detox

Add detox (just a config/test runner change, no new code)