don't vsync; set target FPS to 120-ish

GitOrigin-RevId: 724e876b9a

Shared/SneakGame.cs

@@ -28,6 +28,9 @@ namespace SemiColinGames {
 
     public SneakGame() {
       graphics = new GraphicsDeviceManager(this);
+      graphics.SynchronizeWithVerticalRetrace = false;
+      IsFixedTimeStep = true;
+      TargetElapsedTime = TimeSpan.FromSeconds(1.0 / 120);
       IsMouseVisible = true;
       Content.RootDirectory = "Content";
     }