#186533 properly set group context for comment edit and reply pages. initial patch by sdelbosc. also admin help tweaks.

remove long deprecated submission guidelines preference from admin page. use content type equivalent instead.

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 comments can get emailed even when unpublished and when belonging to an omitted node type.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