message: Moved state scene into element sub property
  Makes way for style property on scene
diff: @@ -8,9 +8,12 @@ class SceneNavigator extends React.Component<any, any> {
  private onNavigate = (oldState, state, data, asyncData) => {
  this.setState((prevState) => {
  var {url, crumbs} = this.getStateNavigator().stateContext;
  - var scenes = {[url]: state.renderScene(data, asyncData)};
  + var scenes = {[url]: {element: state.renderScene(data, asyncData)}};
  for(var i = 0; i < crumbs.length; i++) {
  - scenes[crumbs[i].url] = prevState.scenes[crumbs[i].url];
  + scenes[crumbs[i].url] = {
  + ...prevState.scenes[crumbs[i].url],
  + style: null
  + };
  }
  return {scenes};
  });
  @@ -56,7 +59,7 @@ class SceneNavigator extends React.Component<any, any> {
  willLeave={() => getStyle(unmountedStyle, oldState, oldData, 1)}
  styles={sceneContexts.map(({state, data, url}) => ({
  key: url,
  - data: {scene: this.state.scenes[url], state, data, url, mount: url === nextCrumb.url},
  + data: {scene: this.state.scenes[url].element, state, data, url, mount: url === nextCrumb.url},
  style: getStyle(mountedStyle, state, data, spring(0))
  }))}>
  {tweenStyles => (
  