message: Added stack type check
  TabBarItemView now doesn't just have stack children. When used as segmented tab the children will be ScrollViews
diff: - (void)insertReactSubview:(UIView *)subview atIndex:(NSInteger)atIndex
  {
  [super insertReactSubview:subview atIndex:atIndex];
  + if ([subview class] == [NVNavigationStackView class])
  self.navigationController = [(NVNavigationStackView *) subview navigationController];
  self.navigationController.tabBarItem = self.tab;
  }
  