v0.0.6

The MPM solver is now more bulletproof and support multiple materials including water, jelly, sand and snow (thank Taichi-Elements for me to study from!), also added marching cube node for people who is looking for a plugin to extract surface from point cloud. Also note that the new solver and marching cube node requires CPU or CUDA backend for now as they require sparse data structure.
Related video: https://www.bilibili.com/video/BV1Zi4y1F7nx