Additional ACL utility methods

- Added methods to support front-end admin UI integration e.g. checkPermission()
- Added methods to support pagination on resultsets that have had "@Postfilter" applied.
  (there is no easy/efficient way to count the total results when you apply pagination
   params to a "postfiltered" result set)
Merge pull request #3 from stephanfeb/master

Additional ACL utility methods