an option to turn on/off voxelizer: as per the discussion between @yuanming-hu, @maajor and myself, we may need a de-coupled voxelizer (even a hda) in the future. The Houdini user may directly use the built-in pointsFromVDB node, so no reason for them to pay the overhead.
add a function to clear colliders (useful in cases involving moving walls, spheres etc) that is very common in Houdini's scene.