This is a hacked version of nilquaders hacked version of Russel Marks'
nc100em.

You can get nilquaders version fom here:

  http://www.nilquader.net/nc100em.htm

and Russels original version from here:

  http://www.svgalib.org/rus/nc100em.html

My changes are:

- removed the vgalib and terminal versions
- made the gtk version compile with GTK+ 2.0
- made the sdl version compile with SDL2
- made the menu key available on modern keyboards emulate the NCs menu key
- changed the serial port emulation to allow it to use devices other than
  stdin/stdout. For example, the command
    socat -d -d PTY,raw,echo=0 PTY,raw,echo=0
  creates a nice serial device emulator, whose ends are output by the command.
  You can specify the open end with -s, and use the other end with cat or sx
  or what have you... stdin/stdout is still available by passing - as an arg
  to -s
- some cleanups in the Makefile
- added ncconvert