Authorization project changes done
Adding main heper module for role based access E913
DRY up the authorization system significantly
Merge branch 'master' into e913

Conflicts:
	app/controllers/application_controller.rb
	app/controllers/tree_display_controller.rb
Begin refactoring action_allowed? methods in controllers starting with a-l
Refactor m-z controllers for action_allowed? method
Replace Teaching-Assistant Role name with Teaching Assistant
Show a descriptive permission denied error with controller#action and Role
Allow menu_items#link for all Roles
The first of many authorization tweaks