TssChannel: minimum MIDI support
TssChannel: minimum MIDI support

- nits: change string expression from "..." to '...'
- add setModulePort method for @p
- add keyOn/keyOff to make MIDI handling easy
- add TssChannel.MIDI to manage MIDI devices

toyoshim/tss,toyoshim/tss,toyoshim/tss,toyoshim/tss