Implemented user management app
Altered .gitignore to include __init__.py files
Reimplemented Django REST Framework components for myrg_users
Implementation of OAuth with REST API
Fixes to OAuth implementation

Due to the use of django-oauth-toolkit, some classes needed to be changed.
More information can be found at: https://django-oauth-toolkit.readthedocs.org/en/0.5.0/rest-framework/getting_started.html

Basic testing was performed and appears to work correctly with Django REST Framework resource access permissions.
Altered reference for `settings.LANGUAGES`

Removed the direct reference to `myrg_core`.
Alteration to username form field

* `username` now a regex field
 * Regex restricted to \w, ., - in the ASCII range
 * Dropping Unicode as previously envisaged due to problems with future implementation of messaging system
Field validation for username, email addresses

Moved field validation to model definition.
Reintroducing `SessionAuthentication` auth

`rest_framework.authentication.SessionAuthentication` is required for API frontend login
Minor corrections
Addition of blank myrg_groups

New ```myrg_groups``` Django app to contain group and role models.
modified myrg_groups/models.py
modified models.py
Merge pull request #94 from michaelnamlee/r2d2

Groups - model implementation (p. 1)
Groups - model implementation (p. 2)
Groups (p. 3)
Resolving "Group" conflict
fixed smallintegerfield instead of charfield
added rg_message and rg_repo and its model
fixed foreignkey and added permissions