Fixed bug in JSONQuerySet and its tests
Started tests for models
Many things:
 * changed from absolute imports to relative imports
 * changed from dropping database to wiping it (had a bug with sequential operations) and adapted tests
 * fixed a bug in User.get_or_create_by_email
 * fixed a bug in JSONQuerySetTestCase
 * added a test for unique user_id
Merge branch 'test-models'