Added score, totalScore, and lives. All are implemented and working.

What we need to add:

-making two new asteroids when one is destroyed
-recording scores and being able to update highscores
-automatically appering Alien Ships
-Alien Ships which come on level ups (ie. Bosses)
-Alien Ship Bullet and Ship bullet detection
-two player functionality
-pauses after new games, deaths, and leveling up (ie. when game.resume() is called)
-???