502 on /thumbnail when can't contact remote server

Fix a bug caused by a change in auth_handler function

Remove redundant exception log in /events

Fix the relevant unit test cases

Pull full state for each room all at once

Don't make rooms visibile by default

* Disable the synchrotron on jenkins until the sytest support lands

* Poke jenkins

* Poke jenkins

* Poke jenkins

* Poke jenkins

* Poke jenkins

* Poke jenkins

* Poke jenkins

* Poke jenkins

Enable auth on /publicRoom endpoints

Add some logging for when servers ask for missing events

Don't hit DB for noop replications queries

Add gc_threshold to pusher and synchrotron

Add GC counts to metrics

Add script for running sytest with dendron

Allow setting of gc.set_thresholds

Remove dead code.

Loading push rules now happens in the datastore, so we can remove
the methods that loaded them outside the datastore.

The ``waiting_for_join_list`` in federation handler is populated by
anything, so can be removed.

The ``_get_members_events_txn`` method isn't called from anywhere
so can be removed.

Change the way we do stats for GC

Manually run GC on reactor tick.

Notify users for events in rooms they join.

Change how the notifier updates the map from room_id to user streams on
receiving a join event. Make it update the map when it notifies for the
join event, rather than using the "user_joined_room" distributor signal