TODO

The code should probably have some way to read responses from the
websocket.  Right now it is sending commands but not listening
at all for a response.  If it did, we could make sure shuttle 
commands do not queue up.  We want all jog events to go over 
however so that the motion matches the number of clicks.

The code should be made more compatible with TinyG. Right now it
only has limited testing on GRBL.

The host and port should default to localhost:8989, but they should
be made definable on the command line rather than hard-coded. The
same goes for the device path.

The ability to run without sudo would be nice.  Might just involve
writing up the instructions on how to do so that wiringPi provides.