Graphical improvements

I'm working on a few little things in Q*Bert this morning. Several of
my graphics were antialiased - that is, the used a light gradations
around their edges to make the curves look smoother. This is usually a
very good thing, but if you change background colors, or use
transparency, you get a light grey outline around the object, which
looks terrible. So I cleaned up some of my graphics.
I've also just updated the coily falling routine so that if you can
trick him off the edge of the pyramid, it clears all onscreen enemies,
and you get 700 points. You are also immune to attack when you are on
a platform now.
Next up: dealing with the death of a Q*Bert.