message: Use Tile::position() in StructureManager
diff: @@ -405,8 +405,9 @@ void serializeResourcePool(XmlElement* _ti, ResourcePool& resourcePool, const st
  */
  void serializeStructure(XmlElement* _ti, Structure* structure, Tile* _t)
  {
  - _ti->attribute("x", _t->x());
  - _ti->attribute("y", _t->y());
  + const auto position = _t->position();
  + _ti->attribute("x", position.x());
  + _ti->attribute("y", position.y());
  _ti->attribute("depth", _t->depth());
  _ti->attribute("age", structure->age());
  