This follows the same flows-based flow as regular registration, but as
the only implemented flow has no requirements, it auto-succeeds. In the
future, other flows (e.g. captcha) may be required, so clients should
treat this like the regular registration flow choices.

Include read receipts in v2 sync

Fix broken cache for getting retry times.

Conflicts:
	synapse/handlers/sync.py

Add APIs for adding and removing tags from rooms

Fix broken cache for getting retry times. This meant we retried remote destinations way more frequently than we should

Add missing column

Don't mark newly joined room timelines as limited in an incremental sync

Optionally return event contexts with search results

Add room context api

Implement full_state incremental sync

Fix a 500 error resulting from empty room_ids

A hopefully-complete implementation of the full_state incremental sync, as
specced at https://github.com/matrix-org/matrix-doc/pull/133.

This actually turns out to be a relatively simple modification to the initial
sync implementation.

POST /_matrix/client/api/v1/rooms//send/a.b.c gave a 500 error, because we
assumed that rooms always had at least one character.

Pull out sender when computing search results

Implement rank function for SQLite FTS

Reject events which are too large