GPIO 'shutdown' Kernel module for the Raspberry Pi Model 1B and Model 2

The purpose of this module is to shut down all GPIOs prior to powering off
or rebooting a Raspberry Pi.

The main reason for this is due to there being no real indicators that the
shutdown process has completed. By doing a shutdown of all of the GPIOs (such
that they act like inputs without pullup resistors), you can detect the 'high
impedence' state either with an LED or using some kind of exernal board (such
as an 'ATX Raspi' board). An external board could then detect the shutdown,
and power off the Raspberry Pi safely, and you won't have to fix the file
system due to problems caused by powering it down before it's safe to do so.