Remove redundant module include
Merge pull request #439 from edpaget/rename-application-controller

Rename application controller
explicit doorkeeper namespace declaration

If a constant is already loaded it will be used, e.g. Rails loads ApplicationController and the module declaration uses this instead of the Module namespaced one.
Merge pull request #440 from camallen/rails_autoload_namespaces

explicit doorkeeper namespace declaration
refactor doorkeeper_for and add skip_doorkeeper_for helper