setting for how long the note 'rings' after it's alloted time
in order to support features such as a more legato feel
This should be a number between 0 (no ring) and 1 (double the original
play a single note through its soundfont buffer.
if the note cannot be played because it:
uses an invalid instrument
has a note index that can't be resolved
then treat the note as a Rest, with its stated duration