longer notes don't play for longer times nf-q0kr ← Beads

Twinned from https://github.com/cfsh/ninefold/issues/104 by tools/beads/import_github.py's reconcile pass.

notes should play for their set length, holding a note in the test keyboard should play it as long as held, then switch to the release.

internally we need a concept of 'sustain' perhaps. the sound of the note can gently taper off as modulated by decay, but not too much so a note has a decent sound for a whole bar. Setting decay perhaps sets some kind of rate of decay (log exp idk). Decay = 1 should mean no decay so a note sustains a constant sound