Yield on EDU handling

Dedupe requested event list in _get_events

Update aliases event after deletion

Make registration idempotent, part 2

Remove dead code left over from presence changes

Attempt to update the appropriate `m.room.aliases` event after deleting
an alias. This may fail due to the deleter not being in the room.

Will also check if the canonical alias of the event is set to the
deleted alias, and if so will attempt to delete it.

Make registration idempotent

Make registration idempotent: if you specify the same session, make it give you an access token for the user that was registered on previous uses of that session. Tweak the UI auth layer to not delete sessions when their auth has completed and hence expire themn so they don't hang around until server restart. Allow server-side data to be associated with UI auth sessions.

Add replication stream for pushers

Password reset docs and script

Add a comment to offer a hint to an explanation for why we have a unique constraint on (app_id, pushkey, user_id)

Replace the bash/perl gen_password script with a python one, and write a note
on how to use it.

Persist rejection of invites over federation