Event Medals:
 - Fix ACL bug for viewing medals

Zebra Enhance:
 - AJAX callback is called only in UCP Zebra
 - Zebra module is dynamicly located
 - Users Zebra and Zebra requests are deleted
   in user delete
 - Rework on some SQL queries to be compatable
   with PhpBB 3.1 sql_array builder
 - Some bugfixes