Harpy Update

Harpy is rough at the moment. It can spawn feathers when appropriate,
move in a neat fashion new the top of the stage, and delete itself once
it tries it's done. Modified player a tad so he will now also take
damage from enemy projectiles. Harpy projectile is simply testing code
at the moment. It will implement code to go toward the player's position
once it's finished. May also put a tad of random variation on bullet
trajectories to simulate harpy trying to account for player movement.