Changes

tsk97 Adds generation of notifications when an event is cancelled or
modified
    Modifies EventEJB so that when an event is cancelled or modified,
its attendees receive a
   notification. It also sends the notification by email to those
attendees who have previously
   chosen this feature in their own profile.
    Modifies AdminController, AdminEventsController,
ModifyEventController, and EventResource to
   throw MessagingException, needed by sendEmail.
    Modifies EventEJBTest to throw Exception, needed by modifyEvent and
cancelEvent.