Merge pull request #393 from johngian/864720-event-attendance

[Fix bug 864720] Event attendance in reports only when created
[fix bug 870736] Fixed form validation in events date selector.
Merge pull request #399 from akatsoulas/870736

[fix bug 870736] Fixed form validation in events date selector.
[fix bug 837739] Added email notification when a user changes mentor.
Merge pull request #400 from akatsoulas/837739

[fix bug 837739] Added email notification when a user changes mentor.
[Fix bug 860751] Implement event cloning feature