* Move ApiController to Api/BaseController
* API controllers inherit from Api::BaseController
* Add coverage for various error cases in api/base controller
resources that require a user context vs those that don't (such as public timeline)
/api/v1/statuses/public -> /api/v1/timelines/public
/api/v1/statuses/home -> /api/v1/timelines/home
/api/v1/statuses/mentions -> /api/v1/timelines/mentions
/api/v1/statuses/tag/:tag -> /api/v1/timelines/tag/:tag