remove unused ApplicationPermission
refactor controller permission filters

require_login now ONLY requires login - no further authorization
require_authorization  does the authorization
authorized? will not raise anything - just return a boolean

I hope this reduces the confusion about the different parts some. There
are a number of controllers where we want to require either login or
authorization but not both.

So far i went through all controllers in app and adjusted them.
Will need to go through extension controllers.
Merge pull request #41 from azul/bugfix/6760-page-visibility

Page visibility and controller permission code cleanup