Fixing typo
Fixing bug in participant record

If a participant hasn't been cached in the queue yet then they will
not have their current qnaire, start date, etc, available.  An exception
was being thrown when this happened.  Exception has been removed.
Updating error codes
Adding event list to participant view
Adding cascade rule to role_has_state delete
Merge remote branch 'origin/qa' into release
Replacing defunct set_qnaire() method calls
Adding semaphores to queue repopulate methods

Having more than one user call the repopulate methods at the same
time was causing problems.  A semaphore has been added to fix the
problem.
Fixing bugs in home and site assignment selection
Fixing bug in cron script (invalid date format)
Fixing bugs in assignment select widgets

Modifier was being reused in a loop.  It is now being cloned so that
repeated use doesn't cause a problem.
Further bugs in home assignment select widget
Removing transaction muting

Historically transactions caused problems when using semaphores.
Turning off transactions in the queue has cause other problems,
so for now the transaction muting has been turned off.
Turning off transactions when beginning an assignment
Fixing minor bug
Adding missing DISTINCT keywords to select queries in queue record
Tweaking button text
Fixing bug in assignment select and queue
Refreshing time-based queues when calling get_ranked_participant_list() methods
Tracking old email address when email address is updated