Remove all the conditionals for older Django limitations.
Review Request #5170 — Created Dec. 26, 2013 and submitted
Remove all the conditionals for older Django limitations.
This updates the codebase to depend on Django 1.4 or higher, which is
what setup.py now requires anyway. It doesn't do the is_multi_db()
checks or some of the other checks, as those are no longer required.
Unit tests pass for Django 1.4 and 1.5 for SQLite3, MySQL and PostgreSQL.
