Can use jshint with grunt

and fixed some warnings
Let npm reformate package.json

Whenever I add a dependency using `npm install some-package --save-dev`, it reformtes
this file like this.

I guess we'd better be npm compliant once and for all, rather than fighting against
it each time
Can use nodemon
Updated README
Explain the purpose in the REAdME

When I pointed some friends to this repo, without preliminatory explanation,
it wasn't completely clear why we developped it.
Hence, I try to explain it in our README, because I'm afraid other people
migh also easily miss the point.
(Said differently: it's clear for us because we know our needs, but it's not
 such a common situation)
Merge pull request #6 from AlexFaraino/master

Modify the feedback field that can be confusing
Merge pull request #7 from gturri/grunt

Introducing Grunt
Merge pull request #10 from gturri/readme

Explain the purpose in the REAdME