message: Used array list because index can already exist
  Can already be a scene at index 2 and then add another at 2 will shift it over
diff: @@ -22,7 +22,7 @@ import java.util.List;
  import java.util.Map;
  public class NavigationStackView extends ViewGroup {
  - private HashMap<Integer, String> sceneKeys = new HashMap<>();
  + private ArrayList<String> sceneKeys = new ArrayList<>();
  public static HashMap<String, SceneItem> sceneItems = new HashMap<>();
  protected ReadableArray keys;
  private Activity mainActivity;
  @@ -58,7 +58,7 @@ public class NavigationStackView extends ViewGroup {
  @Override
  public void addView(View child, int index) {
  SceneView scene = (SceneView) child;
  - sceneKeys.put(index, scene.sceneKey);
  + sceneKeys.add(index, scene.sceneKey);
  sceneItems.put(scene.sceneKey, new SceneItem(scene));
  }
  