Brought the UIStack over from the previous game to use here.

src/guecs/sfml/components.cpp

@@ -7,6 +7,7 @@
 namespace guecs {
   using std::make_shared;
 
+  // BUG: this seems to center things wrong in lel layouts
   template<typename T>
     void sfml_center_helper(T& obj, lel::Cell& cell, int padding) {
       sf::Vector2f position{float(cell.x + padding), float(cell.y + padding)};