Added a basic normal shot
Added booleans for the 4 stages of life of a shot: Alive and not shot,
alive and shot, alive and animating, and dead. Alive when isAlive is
true, shot when isShot is true, animating when isAnimating is true, dead
when isAlive is false (set this at end of animation)
Added an inital radius and stored radius for animation purposes.
Moved Circle Exsplosion to circlular shot
added update time steps. This is so it updates uniformly regardless of
computer. Temporary test shot that initialized when click executed.
Crashes if shot extis screen, will be fixed.