Initial migrations for all models.

This is the commit we start using south for all changes we make even
when still in development.

This commit also removes all references to django-audit-log since
we are switching to django-reversion.
Changed setup.py to include admin app and reversion.
Made the search signal handlers only update the index when the
relevant track has a status of `Collection.PLAYABLE`.
New migration for `radio_news`

audit-log removals in the other models.py
Added a few settings/apps:

reversion: The model versioning we use now instead of audit-log
grappelli: For a better looking admin panel
Added some more error handling in the submission process.
Changed radio_users migrations.

This walks around a circular dependency issue with south. The
README is updated to give instructions on how to handle it correctly.