Captain's Log: Stardate 77390.4

Modulators can now modulate Springs! And this means that you can have something crazy like a Modulator modulating another Modulator that's modulating a Spring's stiffness. It all works just like you'd expect, and the data model layer strictly enforces all the invariants that are needed to make it possible on the GPU (single layer recursion, etc).

This is great fun, but right now only MIDI CC modulators are implemented. I plan to do a "build an instrument" demo video, but first I'd like to implement LFO modulators, since I think we can get some really cool effects even from a super basic LFO. Things like Leslie effects should be possible, which I'm excited about. The basic LFOs will just be a set frequency without tempo sync (which will come later).

After implementing the simple LFOs, I'll go through and flesh things out so that every parameter can be modulated, which is now a really easy grunt work task. And then I'll do a demo video.