message: Cache 'm' mode state
diff: @@ -824,6 +824,7 @@ IrcHandler.prototype._onModeratedChannelToggle = Promise.coroutine(function*(req
  "onModeratedChannelToggle: (channel=%s,enabled=%s) power levels updated in room %s",
  channel, enabled, roomId
  );
  + this.ircBridge.getStore().setModeForRoom(roomId, "m", !enabled);
  }
  catch (err) {
  req.log.error("Failed to alter power level in room %s : %s", roomId, err);
  