* [Refactor] Use mdformat instead of markdownlint to format markdown.
* Update unavailiable api links in tutorials
* Update CONTRIBUTING.md
* Use mdformat==0.7.9 to support Python 3.6
* Support HRNet
* Add HRNet configs
* Fix a bug in backward
* Add configs and update docs.
* Not use bias in conv before batch norm
* Defaults to use `norm_eval=False`
* Add unit tests and support out_channels in HRFuseScales
* Update checkpoint path
* Update docstring.
* Remove incorrect files
* Improve according to comments