Combine Create/Delete/Rename mailbox into one event
Consensus seems to be in favour of this change
Do we want to make some events optional?
If yes, then how do we discover which are supported?
(Peter Coates) get rid of the fetch-atts on MessageNew event, move fetch-atts to CONTEXT instead
(Peter Coates) Remove message-search-criteria from the NOTIFY extension, use CONTEXT instead