support hardware in custom sketchbook directory

[soldair]

i use a custom sketchbook directory for my pinoccio files and the arduino ide is totally cool with this but leo.. not so much

use preferences.txt for default config?
http://arduino.cc/en/Hacking/Preferences

the ide saves my custom arduino config in ~/.arduino15/preferences.txt which looks like ini format.
i noticed arduino >= 1.5 creates .arduino15 instead of .arduino folder

[soldair]

i was able to work around it in the board for now. cool stuff man
https://github.com/soldair/leo-board-pinoccio/blob/master/index.js#L20