Add new methods to input handler, add RectangleShape2d, modify test game.

DaggerFramework/Source/SceneGraph/Entities/CircleShape2d.cs

@@ -12,7 +12,7 @@ namespace DaggerFramework.SceneGraph
             renderer.DrawCircle(_radius, _color);
         }
 
-        private float _radius;
-        private Color _color;
+        private float _radius = 16;
+        private Color _color = Color.White;
     }
 }