message: Fixed check - backCrumb null is distance >= 0
diff: @@ -50,7 +50,7 @@ class MobileHistoryManager extends HTML5HistoryManager {
  window.history.go(distance);
  }
  }
  - if (this.backCrumb !== null)
  + if (this.backCrumb === null)
  super.addHistory(url, replace);
  if (title)
  document.title = title;
  