Add Color record struct, small refactor, create a DaggerFramework.SceneGraph namespace.

TestGame/UiLayer.cs

@@ -0,0 +1,22 @@
+using System.Numerics;
+
+using DaggerFramework;
+using DaggerFramework.Rendering;
+using DaggerFramework.SceneGraph;
+
+public class UiLayer : Layer
+{
+    protected override void OnUpdate(double dt)
+    {
+        base.OnUpdate(dt);
+        _time += dt;
+    }
+    protected override void OnDraw(Renderer renderer)
+    {
+        renderer.SetTransform(Vector2.Zero);
+        renderer.DrawRectangle(new Vector2(720 / 2, 1280), Color.Green);
+        renderer.DrawDebugText(new Vector2(720 / 4 - 24, 64), "UI :)", 24, Color.White);
+    }
+
+    private double _time;
+}