start attack from current val if state is > release, else do nothing

start attack from the current value

adds to killlist to be killed after sustain pedal gets lifted

interpolates by cosine, frac in [0,1]

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voice return priority: 0. legato (fixed) 1. same key in sustain 2. free voices 3. oldest voices in release 4. oldest voices

starts release on envelopes if this is the key that was pressed returns true if the voice was actually stopped