Updating touch test for mobile devices

Updated from Modernizr code: http://modernizr.com/downloads/modernizr.js

/*
     * The Modernizr.touch test only indicates if the browser supports
     *    touch events, which does not necessarily reflect a touchscreen
     *    device, as evidenced by tablets running Windows 7 or, alas,
     *    the Palm Pre / WebOS (touch) phones.
     *
     * Additionally, Chrome (desktop) used to lie about its support on this,
     *    but that has since been rectified: crbug.com/36415
     *
     * We also test for Firefox 4 Multitouch Support.
     *
     * For more info, see: modernizr.github.com/Modernizr/touch.html
     */