message: Registered on layout only if current state
  Added navigation listener so it registers after navigation if current
  state. That handles the missed layout scenario
diff: @@ -14,14 +14,23 @@ class SharedElement extends React.Component {
  getStateNavigator() {
  return this.props.stateNavigator || this.context.stateNavigator;
  }
  + componentDidMount() {
  + var stateNavigator = this.getStateNavigator();
  + stateNavigator.onNavigate(this.register);
  + }
  + componentWillUnmount() {
  + this.getStateNavigator().offNavigate(this.register);
  + }
  register() {
  - this.component.measure((ox, oy, w, h, x, y) => {
  var {url} = this.state;
  + if (url === this.getStateNavigator().stateContext.url) {
  + this.component.measure((ox, oy, w, h, x, y) => {
  var {name, children} = this.props;
  var {registerSharedElement} = this.context;
  registerSharedElement(url, name, children, {w, h, x, y});
  });
  }
  + }
  render() {
  return React.cloneElement(this.props.children, {
  onLayout: this.register,
  