Fixes to activities (Thanks Jason)
Commited fix to issue #1637 (http://ocportal.com/tracker/view.php?id=1637). [Orphaned tags could pollute the tag cloud]
Commited fix to issue #1638 (http://ocportal.com/tracker/view.php?id=1638). [Sending a recommend message to multiple people leads to duplicated body content]
Misc fixes