// Use this for initialization
 void Awake()
 {
     GM = FindObjectOfType<GameManager>();
     GM.CreateBackground("Screens/screen_startExit");
     GM.CreateButton(0f, 0.2f, "UI/button_start", StartGame);
     GM.CreateButton(0f, 0f, "UI/button_exit", ExitGame);
     GM.CreateButton (0f, -0.2f, "UI/button_credits", GoCredits);
 }