V0.5 (17 January 2024)
+ Fixes problem when pt3 file has more than 42 patterns.
	Apparently this is a common failure mode, the Demosplash people also
	hit it on their 6809 player but for different reasons.
+ Changes the value return by processor detect to lowercase.
	(so Apple IIe returns 'e' instead of 'E')
	Yes, I shouldn't make a change like this but it simplifies a lot
	of my use cases and it was a pain carrying around the diff 
+ add mute/unmute functions.  Just disables/re-enables the channels
	This is less destructive than using the clear function which
	zeros all registers and is harder/slower to recover from



V0.4 (15 May 2023)
+ Changed so that you can disable the 1.77MHz frequency adjustment at compile
	time.  This saves a few hundred cycles and also some binary size.

	Default is left to have it enabled and switchable so hopefully
	this won't break anything for anyone.