New nodes

• gl/SDFFractalMandelbrot: This allows the creation of 3D mandelbrot fractals inside a mat/raymarchingBuilder. Inspired by https://www.shadertoy.com/view/XsXXWS

And there are also a few additional SDF nodes, that can be used inside this material:

• gl/sdfLink
• gl/sdfOctahedron
• gl/sdfRhombus

Improvements

• sop/reflector: allow blend with geometry color attribute
• refactor camera controls to allow the addition of custom ones via plugins.

Editor

• It is now possible to reset a parameter value to its default by doing a shift+left click on it. (It has always been possible to do with ctrl+click, but this would open a context menu on mac).