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
TokensController and TokenInfoController inherit ActionController::Metal
Merge pull request #443 from jasl/refactor-controllers

TokensController and TokenInfoController inherit ActionController::Metal
Update CHANGELOG. [ci skip]
Releasing version 1.4.0. [ci skip]
Removes deprecated test_redirect_uri
refactor model's modules by ActiveSupport::Concern and move them into models/concerns folder
clean up models validates
rename models' authenticate method
remove unnecessary model_name hacking in Application model