adds PennUser to pennuser namespace
adds custom admin forms
adds custom user manager for PennUser model
adds PermissionsMixin to user model
renames auth_backend -> auth_backends
adds factories for generating user models
adds a slew of tests
merges in current master changes
adds requirements.txt
adds TODO list
Merge pull request #1 from ronocdh/expand-user-model

Adds admin integration for PennUser model