Supporting server-side swift use of Lindenmayer

[heckj]

I don't know if it makes sense or not, but it could be quite possible to use Lindenmayer with Server-side swift (or more generally, swift running on Linux or other platforms). Primarily, it would mean conditionally compiling the existing pieces that require Apple platform specific libraries (CoreGraphics, SwiftUI, and SceneKit) and enabling a secondary 2D (if not 3D) renderer.

One option for the 2D renderer is to borrow from what swift-collections-benchmark has done and enable a simple SVG output renderer as a default 2D renderer if the others aren't available. See that project's DefaultRenderer.swift implementation for the gist of the pattern.

If you'd like this capability, please let me know in this issue - or feel free to jump in and help contribute to enable it.