Adds device detection thorugh screen height to UIScreen
Simple Category, really should be built in to iOS...especially with all of the new screen sizes.
Ex: [[UIScreen mainScreen] isiPhone6]; or [[UIScreen mainScreen] isFiveFivePhone]; The first returns YES if the device is an iPhone 6 or 6 Plus. The second returns YES if the device has an 5.5" screen(6 Plus).