merge from develop (#2)

* 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

* Update CMakeLists.txt

* Add multi-label function for yolov5 (#15)

* Add multi-label function for yolov5

* Update README.md

Update doc

* fix compile for python

* Fix doc and wrong variable name (#17)

* Add multi-label function for yolov5

* Update README.md

Update doc

* Update fastdeploy_runtime.cc

fix variable option.trt_max_shape wrong name

* Update runtime_option.md

Update resnet model dynamic shape setting name from images to x

* add model_zoo yolov6 c++/python demo

* fixed CMakeLists.txt typos

* update yolov6 cpp/README.md

* add yolov6 c++ and yolov6 pybind (#16)

* 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

* Fix outputs order of tensorrt (#18)

* fix trt output order

* Update trt_backend.cc

* add yolox c++/pybind and model_zoo demo

* move some helpers to private

* fixed CMakeLists.txt typos

Co-authored-by: Jason <jiangjiajun@baidu.com>
Co-authored-by: huangjianhui <852142024@qq.com>