Porting Synth_Dexed to Raspberry Pi Pico

I've just put up the second part of my messing around with #PicoDexed - a build of Synth_Dexed for the Raspberry Pi Pico. Summary: It is still only good for 5-note polyphony, but I'm starting to understand why and what I'd have to do about it. I'm still deciding if I want to... All the gory detai...