Add more fields that make their way down to the note and layer structs

- Instrument ID (exists in non-US versions already) [Type: u8]
- Sequence player ID [Type: u8]
- Sequence channel index [Type: u8]
- Sound effect channel table index (default to 0xFF if not applicable) [Type: u8]

These four fields would make identifying specific sound effects / instruments substantially easier, along with making hardcoded low-level sound exceptions easier to implement across the board.