Finish Pi HW application of config

[andrewdavidmackenzie]

Pi HW implementation of Hardware takes GPIO config struct (or changes to it "live") and applies it to the hardware using rrpal, so the pins are all setup correctly.

[andrewdavidmackenzie]

WIP

[andrewdavidmackenzie]

for other types such as I2C, UART, SPIO etc - leave this until after a release-0.1

[andrewdavidmackenzie]

This is covered by other issues about adding specific new functionality currently uncovered (UART, etc)