More fixes for migrations so they don't trip the auto detector in Django 1.7

For some reason a couple verbose_name's did not exactly match what is in the models which would trigger creating migrations locally.
Fixed UserSettings.language to point to settings.LANGUAGES to prevent a similar issue as #3479
Removed Django < 1.5 code path in Django 1.7+ migrations file

Can be guaranteed that get_user_model will be available in a 1.7 migrations file
Also renamed User._meta.module_name => User._meta.model_name since the former is deprecated in 1.7 and removed in Django master (1.8)
Merge pull request #3490 from jsma/migrations-fix

More fixes for migrations so they don't trip the auto detector in Django...