Tox testing to replace the Fabric test

## Very WIP
Throwing this up for input.

Three things I'd like to get out of this:
* `python setup.py test`
* `tox`
* a simpler armstrong.dev

Simplifying:
* VirtualDjango can lose its test runner
* `tasks` can lose/refactor `test()` but I'm not sure about Lettuce and Coverage yet.
* maybe other stuff??