IOWMIFamily.kext Latitude E6420 enable brightness keys

This kext will activate your brightness keys on your Latitude E6420, it will only work if brightness is already working.

This kext is developed by hotKoffy http://www.insanelymac.com/forum/topic/248116-netbook-hot-key-driver-asus-dell-hp/

I've made only a few adaptions