support the Django 1.5 custom user model
Merge remote-tracking branch 'origin/custom-user-models' into scenemachine

Conflicts:
	account/models.py
	account/tests/test_views.py
	account/views.py

Conflicts:
	account/models.py
	account/tests/test_views.py
	account/views.py
whitespace-cleanup
Add an invite user view, form and conf setting
Merge remote-tracking branch 'origin/custom-user-models' into develop
Remove any call to `get_user_model` in the global scope
Merge branch 'custom-user-models' into develop-ledej

Conflicts:
	account/conf.py
Fix for missing reference to custom user model