/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
player = new Sprite(graphics, Content.Load<Texture2D>("playerShip"));
alien = new Alien(Content, graphics, player);
spriteBatch = new SpriteBatch(GraphicsDevice);
background = new Background(graphics.GraphicsDevice, spriteBatch, Content);
bullets = new BulletList();
asteroids = new Asteroid(Content, graphics);
keyboard = new KeyBoardManager(Content);
collision = new Collision(player, alien, bullets, asteroids);
font = Content.Load<SpriteFont>("Font");
}