message: Kept browser history in step with stack
  Go back history same distance as navigating back
diff: @@ -12,16 +12,21 @@ class MobileHistoryManager extends HTML5HistoryManager {
  addHistory(url: string, replace: boolean, stateContext?: StateContext) {
  var title = typeof document !== 'undefined' && document.title;
  + var distance = 0;
  if (!!stateContext && !stateContext.history) {
  var {oldUrl, crumbs} = stateContext;
  var start = !oldUrl ? 0 : oldUrl.split('crumb=').length;
  + distance = crumbs.length - start + 1;
  for(var i = start; i < crumbs.length; i++) {
  let {url, state} = crumbs[i];
  super.addHistory(url, i === 0);
  if (typeof document !== 'undefined' && state.title)
  document.title = state.title;
  }
  + if (distance < 0)
  + history.go(distance);
  }
  + if (distance >= 0)
  super.addHistory(url, replace);
  if (title)
  document.title = title;
  