Usage:

% metahost -v -b 57600 -p COM3 <file.gcode> 

If start.gcode and/or end.gcode are present, prepend/append these

TODO/ideas:
o Detect ctrl-c and use this to cleanly shut down reprap (execute end.gcode)
o Parse entire gcode-file and estimate time to print
o Implement some kind of diagnostics mode to test that the reprap
  responds correctly to commands (cmd-line exerciser?)