Fixes DatabaseWrapper class

I added a Database data member and some (mostly dummy) methods to get the DatabaseWrapper class to actually work with Django (version 1.6.4); before, it kept failing to add users. From the shell (opened by manage.py shell), django.contrib.auth.models.User.objects.create_user was terminating with an AttributeError about DatabaseWrapper missing members, and manage.py createsuperuser was silently failing, although the script claimed that it was successful.