* update model_zoo url

* update mmcv version requirement

* Implement NAS-FCOS

1. Supports NASFCOS
2. Added NASFCOS_FPN
3. Added NASFCOS_Head
4. Added r50 config

* Revert "Implement NAS-FCOS"

This reverts commit ebae11cbbdc5b4f3cc7226c763e9254c94a9c92b.

* Revert "Revert "Implement NAS-FCOS""

This reverts commit 32bca597859a447de62ddf0f2c2f482809730da9.

* Implement NASFCOS

1. Supports NASFCOS
2. Added NASFCOS_FPN
3. Added NASFCOS_Head
4. Added r50 config

* reformatted & use list to build convs in head

1. code refornatted
2. add docstring in nasfcos_head.py
3. use a list of conv config to build convs, rather than names

* cells merged

1. merge cells in nasfpn ans nasfcos_fpn
2. add nasfpn_cell_factory.py

* reformatted

* fixed

* fixed

* Update nasfpn_cell_factory.py

* pre-commit

* bug fixed

* renamed&moved

* not done

* fixed

* fixed

* Delete remove_parawise_cfg_nasfcos_r50_nashead_4x4_coco.py

* fixed

* Create 1x_bias_lr.py

* Revert "Create 1x_bias_lr.py"

This reverts commit 54602ded283a8f646aebfa0f216350fd2ce82e6d.

* fixed

* fixed

* fixed docstring

* init modified

* formatted

* fixed

* updated

* fixed

* fixed

* fixed

* fixed

* fixed

* fixed

* pass test

* fixed

* fixed

* fixed

* rename

* 123

* nasfcos_readme

* Update README.md

* rename & leave empty

* GN->GN-head in README

* fixed

* add compare table fix model_zoo.md

* fix some typos

* minor add

* minor update

* add link for mmdet

* minor update

* migrate to mmcv.cnn.bricks

* remove conv_module, scale, upsample

* update mmdet version and mmcv requirement

* fixed fsaf warning

* Pass momentum_config to register_training_hooks

* Bump mmcv version

* Explicit default

* add norm_eval

* upgrade mmcv

* Use official DDP to implement MMDDP

* update mmcv requirement

* Update the version of MMCV

Co-authored-by: Kai Chen <chenkaidev@gmail.com>

* use git repo instead of pip wheels

* install pycocotools before building mmdet

* fix travis installation

* reorganize requirements, make albumentations optional

* fix flake8 error

* force older version of Pillow until torchvision is fixed

* make imagecorruptions optional and update INSTALL.dm

* update INSTALL.md

* Add note about pillow version

* Add build requirements to install instructions