message: remove RoomViewStore listener from MatrixChat on unmount
  ... to avoid spurious warnings from the tests.
diff: @@ -186,7 +186,7 @@ module.exports = React.createClass({
  componentWillMount: function() {
  SdkConfig.put(this.props.config);
  - RoomViewStore.addListener(this._onRoomViewStoreUpdated);
  + this._roomViewStoreToken = RoomViewStore.addListener(this._onRoomViewStoreUpdated);
  this._onRoomViewStoreUpdated();
  if (!UserSettingsStore.getLocalSetting('analyticsOptOut', false)) Analytics.enable();
  @@ -295,6 +295,7 @@ module.exports = React.createClass({
  UDEHandler.stopListening();
  window.removeEventListener("focus", this.onFocus);
  window.removeEventListener('resize', this.handleResize);
  + this._roomViewStoreToken.remove();
  },
  componentDidUpdate: function() {
  