Big Nose release 2

Due to a bad coding choice, I wound up shipping Big Nose with only the last level, which was a doozy. I had a variable called cur-level, and I kept setting it to 5 or 6 and recompiling to fix bugs.

The real irony was that I already had the code in--but because I hadn't looked at the code for a few years, I didn't even consider searching for "number understood," which would've been a simple check to see if it was done. I wrote the code just before releasing then forgot to use it.

As always when I goof up like this I try to find other small bug fixes to roll into it, or features. So I added some fake-linear directions, updated the walkthrough and put in an ABOUT section.

It's always frustrating to let bugs like that slip through, but I did a lot of work on April 1st, and I put myself in position to roll out a quick initial release.