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

Source/SceneGraph/IMainLoop.cs

@@ -0,0 +1,11 @@
+namespace DaggerFramework.SceneGraph
+{
+    public interface IMainLoop
+    {
+        public void Init();
+        public void Start();
+        public bool ShouldStop();
+        public void Update();
+        public double DeltaTime { get; }
+    }
+}