Use the role hierarchy to get user roles.

Fix for issue #282
Add test cases for AclHelpers
Merge pull request #284 from JoakimLofgren/add-role-hierarchy-support

Support role hierarchies
Fix so anonymous user works in frontend
Add unit tests for anonymous user
Merge pull request #287 from JoakimLofgren/fix-acl-helper

Fix acl helper
Merge branch 'master' into 2.3

* master:
  Add unit tests for anonymous user
  Fix so anonymous user works in frontend
  Add test cases for AclHelpers
  Use the role hierarchy to get user roles.