Add CSM support (composite sinusodial modeling)

[smaybius]

I don't know if all the supported emulation cores support it, but it's implemented in tildearrow's Furnace Tracker and it's in probably all its supported emulation cores. That and also CH3 special mode. Maybe use the interface for FMDrive as reference on how to implement it? Furnace uses the timer and the 4 operators as individual regular channels being controlled with regular row data, while FMDrive's interface involves sliders and other VST controls to control the timer and the 4 operators.

[smaybius]

It's already in Nuked, and probably also MAME

[Wohlstand]

First, to utilise these features, I should extend my WOPL bank format (there is a draft for the next WOPL version 3 where I want to include many stuff, but I still haven't finished it yet. I should select a moment to finish it).