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

Source/Game.cs

@@ -7,12 +7,11 @@ namespace DaggerFramework
         {
             LoadResources();
             OnStart();
+            MainLoop();
         }
         protected abstract void OnStart();
         protected abstract void LoadResources();
         protected abstract void MainLoop();
         public abstract void Shutdown();
-
-        protected Scene scene;
     }
 }