Frotz for TOPS-20

This is the "Bring Zork Back Home" project.

I am, quixotically, in the year 2019, trying to get dumb-frotz running on TOPS-20 on the PDP-10.

The "current-unix" branch contains the modified source code; the "master" branch has mangled filenames and symbols to make TOPS-20 happier, but it's much less readable. There are also branches that represent v2.32r1.

Process "current-unix" with https://github.com/athornton/gnusto-frotz-tops20 to get "master".