Please add license to the code

[TheWWWorm]

Hi!

I want to use your package, but since it is MIT licensed and your .js files does not have mention of license in them, I can't just throw them in my project and use, since MIT states that

A copy of the license and copyright notice must be included with the software.

Can you add something like

/*!
 * @overview es6-promise-polyfill - polyfill of ES6 Promise that is minimal as possible in size
 * @copyright Copyright (c) 2014 Roman Dvornov
 * @license   Licensed under MIT license
 *            See https://raw.githubusercontent.com/lahmatiy/es6-promise-polyfill/master/LICENSE
 * @version   v1.2.0
 */

Thank you!