message: Prevented scene state update if replace
  Need the replaced scene to look the same. Don't want it's navigation context to update because then the replaced scene will update and look the same as the replacee scene
diff: @@ -13,10 +13,16 @@ class Scene extends React.Component<SceneProps & {navigationEvent: NavigationEve
  static defaultProps = {
  renderScene: (state: State, data: any) => state.renderScene(data)
  }
  - static getDerivedStateFromProps(props: SceneProps & {navigationEvent: NavigationEvent}) {
  + static getDerivedStateFromProps(props: SceneProps & {navigationEvent: NavigationEvent}, {navigationEvent: prevNavigationEvent}: SceneState) {
  var {crumb, navigationEvent} = props;
  - var {state, crumbs} = navigationEvent.stateNavigator.stateContext;
  - return (state && crumbs.length === crumb) ? {navigationEvent} : null;
  + var {state, oldState, oldUrl, crumbs} = navigationEvent.stateNavigator.stateContext;
  + if (!state || crumbs.length !== crumb)
  + return null;
  + if (!oldUrl || !prevNavigationEvent)
  + return {navigationEvent};
  + var {crumbs: oldCrumbs} = navigationEvent.stateNavigator.parseLink(oldUrl);
  + var replace = oldCrumbs.length === crumb && oldState !== state;
  + return !replace ? {navigationEvent} : null;
  }
  shouldComponentUpdate(_nextProps, nextState) {
  return nextState.navigationEvent !== this.state.navigationEvent;
  