Completed Part 10

There's now a menu! And you can save your game! Game saves to a file
'savegame' in the local folder, so there's only ever one save going at a
time unless you preserve them manually. Think of it like old-school
Rogue!

Also fun: couldn't find a 160x100 image I liked, so instead I've written
in a custom function to spit out a random star field backdrop for the
main screen. Pretty cool.