Add authentication helpers stubbed out.

This includes the 'current_user' and 'authenticate!' which will utilize
the OmniAuth strategies to allow for access to the API.
Add Auth API mount for OmniAuth strategies.
Refactor models into seperate directory.
Remove auth.rb in favor of directly in api.rb

It seemed to be a lot cleaner this way. I have a feeling I am never
going to want to change this once its working. Keep it simple.
Remove requires that are no longer required.

Mainly due to refactoring and autoloading.