Pr 19 more

This is everything in pull #19 plus an additional commit that fixes tests to work with Django 1.6.

There's still one failing test that I haven't figured out, yet.

```
======================================================================
FAIL: Deleting an instance of MockModel should delete watches.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/willkg/mozilla/django-tidings/tidings/tests/test_events.py", line 360, in test_mock_model
    assert not Watch.objects.count(), 'Cascade delete failed.'
AssertionError: Cascade delete failed.
```

Everything else works super.