Convert imperial tank volume to the metric system.

There are two different ways to specify the volume of a tank. In the
metric system, the tank volume is specified as the water capacity, while
in the imperial system the tank volume is specified as the air capacity
at the surface (1 ATM) when the tank is filled at its working pressure.

To avoid mistakes, the tank volume is now always returned as the metric
volume. For imperial tanks, the tank volume is converted to the metric
representation.
Import Tiny AES128

This imports Tiny AES128 from https://github.com/kokke/tiny-AES128-C for
use in the decoding of OSTC3 firmwares.

This aes-code is released into the public domain.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
This adds code to read OSTC3 firmware files.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add a helper to put the OSTC3 into servicemode

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add utility functions to convert uints to bytes

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add a function to erase the memory of the OSTC3

This is the fist step in the firmware upgrade process.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add function to read the rom from the OSTC3

This is necessary to verify that the memory written got transfered
correctly.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add code to write rom of the OSTC3

This is now you transfer a new firmware to the OSTC3.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Add a function upgrade the firmware in the OSTC3

This function triggers a reboot into the bootloader which flashes the
new firmware to Prom.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Firmware upgrade for OSTC3

This connects the bits and implements firmware upgrade for the OSTC3.

This code is inspired by JeanDo ostc-companion.

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Teach examples/ostc-fwupdate about OSTC3

This teaches the example firmware upgrader about how to upgrade the
OSTC3's.

Signed-off-by: Anton Lundin <glance@acc.umu.se>