/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
Stack <AbstractGameState> Screens = new Stack <AbstractGameState>();
StateManager = new GameStateManager(ref Screens);
StateManager.AddScreen(new MainMenuState(GraphicsDevice, Content, ref Screens));
}