MacBookAir4,1 support patches

3 patches: - one to enable multitouch on the trackpad - one to allow using the Fn keys on the keyboard - and one to make the Bluetooth adapter work The first 2 have equivalents for the MacBookAir4,2 (13") already in Linus' tree. The trackpad patch was added by Dmitry to his tree (though bizarrely no word on the keyboard patch). Not sure what's happening with the Bluetooth patch, no response as of yet. Cheers