Add some smoke tests and fix some bugs

I'm not sure if you're still actively maintaining this project or not, but I'm planning on adding some features I want. Before I did that I wanted to make sure I wasn't going to break anything so I added some tests to the code. Most of them are fairly simple at this point but that ends up covering ~70% of the code so there aren't any little slipups.

Beyond that, I ended up:
* applying PEP8 to some of the files
* fixing a few corner cases in the dashboard view
* resolving a few warnings that crop up in django 1.6/1.7 (there are still some remaining)
* stripping down the is_valid_ipvN_address methods to simply use python's build in `socket.inet_pton()` for validation (I'm assuming there validation is very well tested).

I updated the `.travis.yml` file, though it doesn't seem like there are any builds in travis-ci, so there might be some other problem. I also added a coverage report, which integrates with coveralls.io if you're interested.

If you aren't actively maintaining/interested in maintaining this project anymore, let me know and I can fork it with a rename to avoid conflicts! Thanks!