fix #102113 - prevent users from disassociating themselves from a group if they try and _resubscribed_ to a group

#99282 Wrong default registration setting for node administrators. patch by darren oh. modified by me. similar fix also applied to 'directory' checkbox

noted requirement to re-save group nodes after designating a type as a group. patrch by bonobo. #63288

#87533, new 4.7 only option to sort group homepages in reverse cronological order or by newest comments, patch by ted. note, in 5.0, we have views so this feature is not in 5.0

. patch by Ted. modified by moshe

backport from HEAD, email new group managers and admins, patch by me, modifications by Moshe, #90459

change default email subject and body for notification so that subject never changes and thus braindead mail clients like gmail and entourage will get conversation threading.

#87229 sometimes email notifications were not sent according to prefs. tricky query fix because of mysql NULL oddness

fix audience form bug whereby the group association got lost when posting in simple mode. a byproduct of that was that no private nodes became inaccessible by non admins.