Added Users controller to API
WIP Ability changes to allow record level permissions
Add instance level permissions in Admin controller  /
ResourceController, and encourage more use for CanCan's
accessible_by method. Re-adds ability specs that were in
spree_auth_devise
Drop debugger
Drop admin user controller
Merge branch '1-3-stable' of git://github.com/spree/spree into 1-3-stable