big button: start

* copy debounce arduino script from the web
* some readme notes
send output to serial out
button: revise, get compiling via the GUI
more logging, mpc handler for the big button

call like:

    python arduino.py | python big-button/mpc-button.py --mpd MPD_SERVER

When you push the button:

* if mpd is playing, pause
* if mpd is paused, play

Future ideas: if mpd is stopped, play something at random.