[ ] Do not just return "error 255" if usvg is not installed
[ ] Straighten up svg-flatten input unit handling
[ ] split up python code into modules
[ ] Add backwards-compatible vectorize drop-in
[ ] Figure out handling of drill layers
[ ] Re-publish my own pcb-tools, pcb-tools-extension forks with actual maintenance
[ ] For pattern rendering: validate pattern origin aligns with what the svg spec expects
[ ] Invert SVG color interpretation (use saturation maybe? or sat * val?)
