Adds mixins for Marionette.Controllers

 On branch base_layout_controllers
	new file:   app/assets/javascripts/backbone/lib/concerns/controllers/registration.js.coffee
	renamed:    app/assets/javascripts/backbone/lib/controllers/application_controller.js.coffee -> app/assets/javascripts/backbone/lib/concerns/controllers/show.js.coffee
	modified:   app/assets/javascripts/backbone/lib/controllers/application_controller.js.coffee
	new file:   app/assets/javascripts/backbone/lib/controllers/base_layout_controller.js.coffee
	modified:   app/assets/javascripts/backbone/lib/utilities/mixin.js.coffee