Test refactor

 * Update and refactor the test suite somewhat. Now tests create the data fixtures that they need and cleanup after themselves afterward. As a result, each test can run in the same database environment - no need to drop, create, and update the schema with each test. The end result is a test suite that runs in 5 seconds, where it used to be 2 minutes.

 * Removed the unnecessary data fixtures, and the lom:purge command will now ask if it should attempt to load fixtures at all.

If there's data in your test database, you may need to drop and recreate it the first time. `./app/console --env=test lom:purge` makes that easy. Just don't load any fixtures for the tests anymore.

All tests passing in Travis.