I added logic to the game so now when a UFO is killed, it will break
apart into pieces to add more of an impac to game play.

I also touched up the HUD a bit by making the icons on the left side
that display the super shield, the bomb and the thruster level a bit
smaller.
Merge branch 'development'

When the player or UFO is killed, the respective ships break apart into a bunch of pieces.

I also touched up the HUD a bit with regard to the players thruster.