Was self raised by the directional pad?

Property definitions

android :: gamepad $ AndroidKeyEvent :: is_dpad
	# Was `self` raised by the directional pad?
	fun is_dpad: Bool
	do
		return is_dpad_up or is_dpad_down or is_dpad_left or is_dpad_right
	end
lib/android/gamepad.nit:34,2--38,4