Use clipping to render layers with `startLayer` and `endLayer`

Part of https://github.com/remcoder/gcode-preview/issues/221

This PR ended up needing more changes than I initially anticipated, but it's leaving the files in a better state than when I started.

The first implementation of clipping turned out to be easy to add. It became complex after needing to batch lines together as well to have a single material with the clipping planes.

Progressive rendering is always a forcing function for good implementations. You'll notice how clean the rendering methods turned out! All lines and tube use some sort of batching per color, and batches can be build progressively. The difference with how it's implemented. Instead of using layers, it uses subsets of paths.

Todo

[x] Implement for lines
[x] Implement single layer mode ~- [ ] Implement a non-planar version~ The API assumes layers. Non-planar jobs need to use the tolerance in order to split into layers that are usable. option: https://github.com/remcoder/gcode-preview/issues/241
[x] ~Use clipping for~ repair the progressive rendering mode
[x] Fix the tube geometry to be positioned on top of the z position
[x] Add tests
[x] Remove the plane helpers

xyz-tools / gcode-preview

Use clipping to render layers with `startLayer` and `endLayer` #234

Todo