#182936 Make it possible to add tabs to the group home via Views (and only the group home page). patch by KarenS.

Public checkbox makes no sense if access control is disabled. Also add hook_requirements() check so admin creates his node type and assigns as group type.

#179433 and #178294. comments can get emailed even when unpublished and when belonging to an omitted node type.

rework og_mail query again so it is slightly less efficient but more accurate and compatible with postgres and any others.

eliminate duplicate email notfications by switching from DISTINCT() to GROUP BY. I need someone to check this query in Postgres and suggest a change as needed. I don't care which group is returned alon g with the subscriber's email address. I do care that the group info is consistent.

#175567 better fix for error in your SQL syntax in og_mail(). patch by grugnog2. modified by moshe weitzman.