Splash screen!

Added a splash screen to the game, took like 5 minutes, but recoded some architecture to made the implementation of the main menu easier. Which was basically why I did it. But we still have to figure out how we want to handle the swapping between the screens. My experience says store all the Screens in a hashmap and make a custom method for swapping between the screens in a Main.java class. Will need to look through other solutions to motivate why we would do it like this.