message: Moved continuation override into did mount
  Matches the add/remove listener React pattern
diff: @@ -10,17 +10,17 @@ class NavigationHandler extends React.Component<{ stateNavigator: StateNavigator
  var { stateNavigator } = this.props;
  this.navigateHandler = () => this.forceUpdate();
  this.originalGetNavigateContinuation = stateNavigator['getNavigateContinuation'];
  - stateNavigator['getNavigateContinuation'] = this.getNavigateContinuation.bind(this);
  this.state = { stateNavigator };
  }
  componentDidMount() {
  this.props.stateNavigator.onNavigate(this.navigateHandler);
  + this.props.stateNavigator['getNavigateContinuation'] = this.getNavigateContinuation.bind(this);
  }
  componentWillUnmount() {
  this.props.stateNavigator.offNavigate(this.navigateHandler);
  - this.state.stateNavigator['getNavigateContinuation'] = this.originalGetNavigateContinuation;
  + this.props.stateNavigator['getNavigateContinuation'] = this.originalGetNavigateContinuation;
  }
  private getNavigateContinuation(oldUrl: string, state: State, data: any, url: string, historyAction: 'add' | 'replace' | 'none', history: boolean): (asyncData?: any) => void {
  