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

fastdeploy/fastdeploy_runtime.py

@@ -51,5 +51,5 @@ class FastDeployModel:
     @property
     def initialized(self):
         if self._model is None:
-            return false
+            return False
         return self._model.initialized()