[author] MooTools core 1.5.0

Hi, I'm adding the latest major version of MooTools we just released: 1.5.0.

The source files are the same you can download from the http://mootools.net/download page.

MooTools comes in two versions, a version which includes a compatibility layer, so that it's backward compatible with any code written for MooTools 1.2+ and one without this layer.

For the minified version I originally included the yui compressed version we are serving from our website, after reading your Readme though I see you prefer uglify instead, so I updated those files to use it.

I checked the previous version that was uploaded (1.4.5) and notice that you've run a minifier on our already minified version, and also by doing so you stripped all the comments including the MIT license and copyright bits which you shouldn't had removed as per license instructions.
In order to avoid this I renamed the minified version as .min.js as I believe you checked the extensions for deciding if a file was minified or not. If this is not the case please let me know.
The minified files includes a manually stripped down version of the license comment. 

I also updated the package.json to reflect our package.json: https://raw.githubusercontent.com/mootools/mootools-core/1.5.0/package.json from which I removed the `main` property which is wrong anyway, and the `scripts` and `devDependencies`  properties which are not needed since I'm pushing the build version.

I noticed that there was a `filename` property, if you use it please let me know what it's used for, so I can update the PR to include it.

Thank you, 
Cristian -- MooTools Core Developer.