MD25 Motor Controller Driver

I recently wrote a driver for the MD25 motor controller board here: http://www.robot-electronics.co.uk/htm/md25tech.htm. I am using it to control a segway-like robot with two wheels.

This isn't ready to merge yet as I haven't started live testing, but I would appreciate some feedback in the meantime.

The MD25 also has the ability to read the encoder information/ battery voltage/ motor current,  which could be used to assist with indoor navigation etc. So it might make sense to add a new uORB topic for at least the encoder data/ possibly the motor voltage/current.