After realizing that the sleep time doesn't delay the closing of the …
from the user's perspective (as it's already closed before the sleep occurs),
go ahead and give it a more generous amount of time to wait for the Qt
thread to finish.
Fix a potential memory error in the additive oscillator if it was edited
while notes were playing. Since each voice caches a reference to the
pointer for the wavetable, all voices must have their references reset
if a wavetable is replaced by the pointer-swap...
Fixed problems with the fact that the MIDI file's note-off scheme
could be in either note-off events, or just by note length...
(PyDAW operates on note_length only, recorded MIDI is converted to that