Add initial game code

scripts/GameState.cs

@@ -0,0 +1,21 @@
+using System;
+
+public partial class GameState
+{
+    public Universe Universe { get; private set; }
+
+    public void New(Universe newUniverse)
+    {
+        this.Universe = newUniverse;
+    }
+
+    public void Load()
+    {
+        throw new NotImplementedException();
+    }
+
+    public void Save()
+    {
+        throw new NotImplementedException();
+    }
+}