Detectron2-Densepose-IUV2XYZ

Densepose is an excellent detection project. Currently, Densepose is implemented by Detectron2 framework, which document is not detailed. So I transfer some Densepose code from Detectron1 to Detectron2, and reaccomplish functions like IUV extraction from image and IUV projection on SMPL model.

If you have any issue about this code, leave a comment in Issues. I'll answer it as soon as possible.