Add SDF Viewer as another renderer for this library

[Yeicor]

I made a real-time, cross-platform, language-agnostic SDF Viewer application, and integrated it with your SDF library. It works similarly to sdf3ui but has some extra features (AFAIK):

• Different rendering algorithm that allows observing the model preview while it is being loaded.
• Shows the hierarchy of SDFs that build the final model and can render any subtree.
• Support for textures and material properties (and even exporting them).
• Support for customizing parameters in real-time from the UI without modifying the code (useful for publishing, it also listens for code changes and refreshes the view)
• You can publish your SDF by uploading a file to a server and sharing the renderer link (renders and allows to customize and generate a mesh of the SDF in the browser without any backend).
• More meshing algorithms running on all platforms (although speed is not a concern).

Check out https://github.com/Yeicor/sdf-viewer and https://github.com/Yeicor/sdf-viewer-go for much more information.

A little demo:

demo.mp4

Note that I had to use TinyGo instead of the Go Compiler, so the builds (after the code change) are a lot slower than Go.

Another useful feature is verifying that the SDF is properly defined, as a bad SDF will show artifacts on the SDF renderer (even if marching cubes or other algorithms seem to return a valid result). For example, it seems like ScaleUniform3D may not be correct (I haven't looked at it, it may also be an error with the integration), as it gives some render issues:

• Without ScaleUniform3D:
  

• With ScaleUniform3D:
  

[soypat]

Amazing stuff! Thanks for the PR and for letting me know of the ScaleUniform bug. Let me know if you want to open an issue on it (or I'll do it sometime this week). As for this PR, LGTM!