Add support for Mobile Detect library http://mobiledetect.net/

Mobile Detect is an actively developed PHP class that provides a large quantity of mobile and tablet detection tools.

My thinking was to remove the current "MobileBrowserDetector" class and instead connect the mobile module to the Mobile Detect class (allowing the core dev's to focus on integrating this class with Silverstripe, rather than writing mobile detection rules).

All thoughts, comments, critiques welcome :-)

Mo