Updated event edit to add a bold notice at the top of the page if there was a reason...

Updated event edit to add a bold notice at the top of the page if there was a reason the event edit could not be submitted.
Now setting page modified status to prevent user from being able to leave the page after a failed submit without answering a pop-up that they want to leave the page.
Sorted out problems with am/pm pick-list when editing start and end times. That was a fix to js/datetimepicker in glm-member-db plugin.