API renames, change ref renderer to in renderer in IDrawable, make Layer implement IDrawable.

Source/Entities/Sprite2d.cs

@@ -14,7 +14,7 @@ namespace DaggerFramework
             _texId = renderer.LoadTexture(_texture);
         }
 
-        public override void OnDraw(ref Renderer renderer)
+        public override void OnDraw(in Renderer renderer)
         {
             renderer.DrawTexture(_texId, Color.White);
         }