MA2输出MIDI的命令，可用于控制MIDI控制器，以及MIDI控制的播放器等
基本格式如下：
MidiNote [note]
MidiNote [midichannel].[note]
MidiNote [note] [velocity]
MidiNote [midichannel].[note] [velocity]
MidiNote [note] Off
MidiNote [midichannel].[note] Off
MidiNote [note] [velocity] Off
MidiNote [midichannel].[note] [velocity] Off