message: Removed redundant hide
  Used hide when navigating forward so that the new screen animates over the top of the old. But it doesn't work when doing a replace - the animation always happens wrong way round - so removing it
diff: @@ -139,8 +139,6 @@ public class NavigationStackView extends ViewGroup {
  FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
  fragmentTransaction.setCustomAnimations(enter, exit, popEnter, popExit);
  fragmentTransaction.replace(((ViewGroup) this.getParent()).getId(), new SceneFragment(key), key);
  - Fragment replacedFragment = fragmentManager.findFragmentByTag(oldKey);
  - fragmentTransaction.hide(replacedFragment);
  fragmentTransaction.addToBackStack(String.valueOf(crumb));
  fragmentTransaction.commit();
  }
  