Further code size reductions

Hi! I just ... was bored, and decided to go another round trying to shrink the code size of the minimatrix firmware.

If my comparison powers are working, the latest commit makes the output 88 bytes smaller than your HEAD.

Which ... isn't a lot at all, but at least it's something, right? :)

I haven't tested this on the actual hardware, so merge at your own risk. I'd be very interested to hear if it works, if you decide to use this code.

Also, I realize that offer for free hardware probably expired long ago, and I already got mine. This was just for fun.

Regards,

/Emil