Release notes 6/16/2014

@mhoeber @lamagnifica Please review. Built HTML version at http://draft-release-notes-6-16.readthedocs.org/en/latest/06-16-2014.html.
combine with the first bullet? both are updates tot he Bul email section...
"Updates to describe the workflow and possible states for bulk email tasks, and circumstances in which enrolled students do not receive bulk email messages, to the `Bulk Email`_  section."