* Defaults to return tuple in all backbones.
* Compat downstream of swin transformer.
* Support tuple input for multi label head and stacked head.
* Fix backbone unit tests for tuple output.
* Add downstream inference unit tests for mmdet.
* Update gitignore
* Add unit tests for `return_tuple` option
* Add unit tests for head input tuple.
* Add warning in `simple_test`
* Add TIMMBackbone return tuple.
* Modify timm backbone unit test.
* Add wrapper to use backbones from timm
* Add tests
* Remove timm from optional deps and modify GitHub workflow.
Co-authored-by: mzr1996 <mzr1996@163.com>
Ma Zerun
Miras Amir