decoder (and encoder) for quaternions sent from a joycon. Based heavily on reverse engineering done by hexkyz.

for those who want to use it as a reference, I hope this is readable, but I may have gone a bit overboard on using fixed point types.

can't be arsed to setup a LICENSE for this at the moment, but I'll proabably go with something appropriately prermissive. poke me if you care and I haven't gotten around to it yet.