Cleaned up some test code docstrings and method names.
Cleaned up some test code docstrings and method names.

(Mostly copy-and-paste leftovers from django-registration.)

noderabbit-team/django-invitation,mgaitan/django-invitation,arctelix/django-invitation,adieu/django-invitation,ruiwen/django-invitation,mentionllc/django-invitation,deschler/django-invitation,lubosz/django-invitation,mgaitan/django-invitation,jannon/django-invitation,arctelix/django-invitation,jannon/django-invitation