Bug fix, registration & validators

- Bug fix for channel categories not returning an array
- New registrationResponseMaker
- Correct in commenting
- New ApiValidator
- New RegistrationValidator
- Added new response codes
- ApiController::respondWithError now accepts a data array so we can
send back any data. Specifically validation messages in the case of
this update
- Updated register controller to use IOC container for dependency.
Removed all CMS type actions
- apiErrorResponse now accepts optional data array
- New IOC bindings for userRepository and userTransformer
- New routes for registration
- Updated creating a new user to fit with registration requirements