MSM5232 instrument editor

the instrument editor for MSM5232 consists of these macros:

Volume: volume sequence.
- only has effect when the envelope mode of a group is set to External.
Arpeggio: pitch sequence.
Group Ctrl: group control sequence:
- sustain: enable sustain mode.
- 2': enable 2' overtone.
- 4': enable 4' overtone.
- 8': enable 8' overtone.
- 16': enable 16' overtone.
Group Attack: set attack rate of group.
Group Decay: set decay rate of group.
Noise: toggle noise mode.