Removing RealSense dependency from Kaya Example code

I have just built Kaya and was disappointed to realise (well too late) that the D435i isn’t supported, and that RealSenseLib isn’t easily patched to make it work.

I would like to put that to one side for now (hoping that D435i support comes in the next release…) and concentrate on the fundamentals of the drive system and so on.

The joystick example depends upon the RealSense camera being detected. Sorry to be that super noob, but could anyone give me a steer regarding how to go about cleanly stripping the RealSense camera dependency out of the Kaya joystick example code?