Fixes a half dozen bugs.

Changelog:

 - fix: Event End Time Missing (perlDreamer Consulting, LLC.)
     http://www.plainblack.com/bugs/tracker/event-end-time-missing
 - fix: EMS - Adding Prerequisite sets.
 - fix: Multiple Instances of EMS displaying on View Purchase
 - fix: invalid group ids will stall sending queued mail
 - fix: Low UI level on Visitor prevents email password recovery form from working
 - fix: requesting an password reset by sets all user's auth settings to Visitor's