yaht sources!

Many thanks to Hal Daume III for the tex sources to Yet Another Haskell Tutorial. As soon as I have time to work on the import, the Haskell wikibook will include the entirety of YAHT. We'll do this in two phases, I think. First I'll create a subpage of the wikibook containing the original YAHT. People can continue to use and modify that version indefinitely, because hey, it's pretty damn good. The second phase will consist of us wikibookians mashing up our stuff with YAHT stuff. Lot's of borrowing, moving, deleting and debating. It might come out great, best of both worlds, or it might just end up being horribly clumsy, but it'll be a worthwhile experiment!