Adding failing tests for calling just the action, instead of :create_action_name and :deliver_action_name

Delegated ActionMailer::Base.deliveries to Mail.deliveries, added callback support in Mail to call ActionMailer on delivery, moved deliver to deprecated API in preparation for new API

Remove URI object from ActiveResource notification, send the :mailer class in AM (like in AP#process_action) and remove locale instrumentation.

Mailer should give self as payload because it contains all the information needed (as the template rendered and the mailer name).

Remove duplicated url_for code and move methods shared between ActionMailer and ActionController up to AbstractController.

controller_path is required by ActionView, so move it up to AbstractController and refactor AbstractController::Layouts.