Added 'official' Raspberry Pi HF cross compilation environment from
https://github.com/raspberrypi/tools
Added WiringPi as a submodule. This is a fork of the WiringPi project
from https://projects.drogon.net/raspberry-pi/wiringpi/ so I can make
local changes while tracking the upstream.
Started work on the make system for the tools and support libraries.
Working on the make system.