message: Forward declare Thing in Tile
diff: #pragma once
  #include "../Common.h"
  -
  #include "../Mine.h"
  -#include "../Things/Thing.h"
  -
  #include <NAS2D/Renderer/Point.h>
  #include <NAS2D/Renderer/Vector.h>
  +class Thing;
  class Robot;
  class Structure;
  