cheapglk (cheapass implementation of the Glk API)

This is the simplest possible implementation of the Glk API. It uses
stdio.h calls (fopen, putc, getc), but not any of the curses.h calls
(which handle cursor movement and unbuffered keyboard input.) So
there's no way it can support multiple windows, or a status bar. In
fact, this library only allows you to create *one* window at a time,
and that must be a TextBuffer. Fortunately -- well, deliberately --
TextBuffer windows are very simple; all the library has to be able to
do is printf() straight to stdout.
