Userscript version ready

Done this from @hugomg code and updated.

Actually, the code is pretty simple to update. Just added some var and execute them at the end. (+ we remove all `"use strict";`on the code except at the begging)

Also, Greasemonkey and Tampermonkey will be able to update the code with this file on master. 
After updates, we just need to change the version (and the code, of course) and users will get a notification for the update (or it'll be automatically updated)