fix(view): change ViewPort to add View synchronously

  Before:

      viewPort.insert(a);
      viewPort.remove(a);

      viewPort.views == [a]

  After:

      viewPort.insert(a);
      viewPort.remove(a);

      viewPort.views == []
Yes, that's what should happen. The DOM nodes should be added and then removed. I think it won't cause any issues, but we should test clients.