Particles Tests - 2

Description

Yet another nice looking pointcloud ;) Those latest models are just the results of me testing stuff to update and improve a small C++ particle simulations code I previously used to create [this model ("Need some space?")](https://sketchfab.com/3d-models/need-some-space-d6521362b37b48e3a82bce4911409303). I've made the code a bit more robust and easier to setup, tweak, and run... And I've just fixed some huge memory leaks and drastically improved its performance, Yipiii !