Improved the UFO and UFO Block

-Added randomly-colored particles to the UFO and its block
-Added three new sound effects to the UFO
Added the volume-adjusting functionality for sound and music

-Created config._sounds, a list of all sound effects
-Added new sound effects for the cursor
Fixed some bugs

-After a game ended, Enemys would not fire again until you restart
-Cut off some bits of 2.ogg so that it properly loops
-enemysquadron.celebrate() would treat BallOfLights as Enemys, crashing the game
Improved animation and graphics a bit

-Added a new particle effect for when the Ship appears
-Began implementing the Enemy's celebration animation (they no longer sit there when the game's over)
-Added a red line to the top of bg.png to show where the Game Over line is
-The game now only loads and blits the top half of the Earth graphic
-All sound effects stop when you exit a game
-Forgot to commit select.wav