By default we leave it at the default value of 12. But now we can reduce
it for preparing users for loadtests or running integration tests.

Update the v2 sync API to work as specified in the current spec.

Remove unused room_id arg

Bounce all deferreds through the reactor to make debugging easier.

If all deferreds wait a reactor tick before resolving then there is
always a chance to add an errback to the deferred so that stacktraces
get reported, rather than being discarded.

Update the v2 filters to support filtering presence.

Split out the schema preparation and update logic into its own module

Apply the filter the 'timeline' and 'ephemeral' keys of rooms.
Apply the filter to the 'presence' key of a sync response.

SH CAS Required Attribute

Split the sections of EventStreamHandler.get_stream that handle presence

Fix some races in the synapse presence handler caused by not yielding…

Allow optional config params for a required attribute and it's value, if specified any CAS user must have the given attribute and the value must equal

Provide ability to login using CAS