Base conversion (and alphabetizing imports)

Racpete can now translate numbers between bases! I also made things alphabetical because it was bothering me. The convert-base code is pretty ugly, I think, but I couldn't figure out a good idiomatic way to do it. Point me in the right direction and I can fix it :)
Huh, okay. I'm going to leave it as-is because we already have some tests there, and it seems more convenient to have them all together. However if @bboston7 wants it differently I'll move it.