No more need the buffer tools module

[hashisan-atBridge]

in GrovePi/blob/master/Software/NodeJS/libs/grovepi.js
var bufferTools = require('buffertools').extend() has been declared but not used,
and package.json also has "dependencies" entry of "buffertools": "2.1.*".

buffertoools module had been depredated.
we are using GrovePi module for our Node-RED custom nodes for GrovePi access and got an error on nodes install process.
could you please delete buffertools require statement and package.json entry.