Add back example output images as lfs tracked files (#166)

* lfs track images now

* add back example images

* modify paths

* modify paths part 2

* correct paths in each model's readme

README.md

@@ -23,7 +23,7 @@ python demo.py --help
 
 ### Example outputs
 
-![webcam demo](./examples/wechat_qrcode_demo.gif)
+![webcam demo](./example_outputs/wechat_qrcode_demo.gif)
 
 ## License