message: Returned shared els when oldUrl === ''
  If don't use MobileHistoryManager (hash or html5 instead) then the start url is empty string on first load. If don't return shared elements when old url is empty string then the first navigation doesn't animated the shared element
diff: @@ -58,7 +58,7 @@ class NavigationMotion extends React.Component<any, any> {
  delete this.sharedElements[scene][name];
  }
  getSharedElements(crumbs, oldUrl) {
  - if (!oldUrl || crumbs.length === oldUrl.split('crumb=').length - 1)
  + if (oldUrl === null || crumbs.length === oldUrl.split('crumb=').length - 1)
  return [];
  var oldSharedElements = this.sharedElements[oldUrl.split('crumb=').length - 1];
  var mountedSharedElements = this.sharedElements[crumbs.length];
  