We have a few apps on Djblets that could conflict with app labels from
the consumer. Django didn't used to care about this, but starting in
Django 1.7, there's an app registry that ensures uniqueness.

To fix these conflicts, AppConfigs are now registered for each app,
with only a couple exceptions. Not all of our apps need to be added to
INSTALLED_APPS, but since they may be, we're covering nearly all of
them. The table names have also been updated to use the original names,
for backwards-compatibility.

This will only affect Django 1.7+, and has no bearing on Django 1.6
(which doesn't let you specify app labels anyway).

No longer saw problems with Django complaining about duplicate apps.
Unit tests pass (along with all other upcoming changes).