Refactoring ES6, no new Buffer()

[nolan-vanmoortel]

Let me begin by saying thank you for the work done.
Your module binn.js have been very helpful at MintT.

I made a refactoring using the latest concepts of ES6 and in particular on the new Buffer() which are deprecated.
I took advantage of the occasion to apply an eslint-airbnb and tests with chai.js.

-Vanmoortel Nolan

[kroggen]

Hi!

Thank you for the contribution!

Unhappily I cannot accept it on the master branch because it has so many changes, it adds new dependencies and many people still prefer the old Javascript.

So I added a link to your version on the README for ES6 users.

I also recommend using lower case letters on commit messages, unless your company requires the opposite.