I couldn't get these to work yet:
Alt-M: mark
Alt-P: paste
Alt1-12: mute channel

Mark/paste: how is it supposed to work?  Does Alt-M select the whole
channel automatically?  Can there be a way to select part of a pattern?
I remember Scream/Impulse tracker had Ctrl-D to select 16/32/48/64 rows
each keypress.  Or, maybe Alt-M to mark top of selection, arrow keys,
then Alt-M again to mark bottom of selection and copy.