v8.0

• changed: get group tool options using the new helper function
• changed: group sidebar cleanup reworked
• changed: moved different autojoin groups to own functions
• changed: moved unregister widget from ready to init event
• changed: required Elgg version set to 2.2
• fixed: check correct plugin setting for group creation
• fixed: deprecated notice when transfering group ownership
• fixed: force notification settings don't apply
• removed: custom icon serving handling