Start adding tests for auth.models

Currently just testing that groups record user membership correctly.
Add tests for has_permission

Fixed bugs in has_permission, should fix #25.
Add test for looking up permissions of a division
Clean up imports in auth/test_models
Reorganize/rework how tests are run/discovered

Also pulled TestApp into a util package.
Do minimal app configuration for testing
Start adding tests for views

Start with a test ensuring that anonymous users are redirected to log in.