- also remove m.room.aliases support as they were wrongly implemented
and now obsolete
- don't count invited and joined members according to m.room.member
events anymore as it was also wrongly implemented
(only when prev!==new membership, but on initial sync we only get
last member event, which might have been a nick change
when doing a limited sync, and a new fragment is created,
this._lastLiveKey is updated immediately. If the transaction
would then fail, the fragmentId in this._lastLiveKey was incremented
but the fragment wasn't written to the store, so if sync is resumed
and would subsequently succeed, fragmentIds would be assigned to events
that don't have a corresponding fragment in the timelineFragment store.
This would throw errors when trying to load the timeline,
breaking the whole app.
This changes SyncWriter to only update this._lastLiveKey in
the emit phase, when the transactions has been committed already.
