Removing .load_and_authorize_resource

The CanCan.load_and_authorize_resource was misbehaving in integration
tests. I suspect this could've become a problem in production as well.
So I have since replaced the .load_and_authorize_resource with the
configurable:
  Controller.excluded_actions_for_curation_concern_authorization
Merge pull request #22 from jeremyf/replace-load-and-authorize

Removing .load_and_authorize_resource