GitLab

* some modifications for pointnet2

* temporarily save changes

* move files to new directory point_transformer

* implement point transformer for classification

* restore train_cls in pointnet

* implement point transformer for partseg

* fix point transformer for nan loss

* modify point transformer for cls

* modify training setting

* update transformer for cls

* update code

* update code for latest performance

* update the example index

* some minor changes
Co-authored-by: Tong He <hetong007@gmail.com>