message: Use proper includes for IconGrid
diff: #pragma once
  -#include "UI.h"
  +#include "Core/Control.h"
  +
  +#include "../Constants/UiConstants.h"
  #include <NAS2D/Signal.h>
  #include <NAS2D/EventHandler.h>
  +#include <NAS2D/StringUtils.h>
  #include <NAS2D/Renderer/Point.h>
  #include <NAS2D/Renderer/Vector.h>
  #include <NAS2D/Renderer/RectangleSkin.h>
  