Merge branch 'master' of github.com:matrix-org/synapse into sql_refactor

Conflicts:
	synapse/storage/_base.py

synapse/storage/schema/presence.sql

@@ -16,6 +16,7 @@ CREATE TABLE IF NOT EXISTS presence(
   user_id INTEGER NOT NULL,
   state INTEGER,
   status_msg TEXT,
+  mtime INTEGER, -- miliseconds since last state change
   FOREIGN KEY(user_id) REFERENCES users(id)
 );