* update .gitignore
* Added checking for cmake include dir
* fixed missing trt_backend option bug when init from trt
* remove un-need data layout and add pre-check for dtype
* changed RGB2BRG to BGR2RGB in ppcls model
* add model_zoo yolov6 c++/python demo
* fixed CMakeLists.txt typos
* update yolov6 cpp/README.md
* add yolox c++/pybind and model_zoo demo
* move some helpers to private
* fixed CMakeLists.txt typos
* add normalize with alpha and beta
* add version notes for yolov5/yolov6/yolox
* add copyright to yolov5.cc
* revert normalize
* fixed some bugs in yolox
* Add UltraFace Model support
