Fixes initial migrations of entries, crm, and contracts

I put crm models in the entries migration so circular dependencies won't take
several migrations to fix up. Used a depends_on clause in contracts so
that it will run after the entries migration. Had to add a second
entries migration for entrygroup to tie contracts and entries together.

This last point means that when deployed, we will need to run::

    django-admin.py migrate entries --fake

This will line up our south migration history with the number of migrations for
everything.