#2 Display correct answers

[Glen Ditchfield]

* When a comet hits a city, display the correct answer, thus
converting a disaster into a learning experience.
* Comets sizzle when shot.
* Compilation and efficiency tweaks.

Check out the cvs source as of 2005-03-07, and in the
check-out directory execute "patch -p0 <answer.diff". Copy
the .pngs to data/images/comets, and the .wav to
data/sounds.