Update reference PDFs and data file.

I made things more consistent. All the nodes marked in the *_paths.pdf
files now match their counterparts in the data file. I also made every
floor exit explicit by giving it the suffix '_exitnode'. That way a
reader can distinguish between things like space_theater_exit (not a
real floor change) and cyberspace_exit (stairs). I haven't made any
distinction between stairs and elevators. I'm not sure how we should
handle that.