Modify and merge in feature/node-stacking branch

[halmueller]

Polish Jacopo Gasparetto's node stacking work and merge it into mainline.

[halmueller]

I'm doing this work over in my private fork, but there's a feature branch on primary repo for anyone who wants to watch.

[Pilot-Marc]

I like this feature, thanks for finishing this up 👍

[jacogasp]

Hello buddies, here the branch with a lot of fix and improvements after @halmueller suggestions. Now it fully use simd for computation