* add isort config

* use isort to sort imports

* add isort to travis

* format the codebase with yapf

* add yapf to travis

* added cityscapes

* updated configs

* removed wip configs

* Add initial dataset instructions

* Add cityscapes readme

* Add explanation for lr scaling

* Ensure pep8 conformity

* Add CityscapesDataset to the registry

* add benchmark

* rename config, modify README.md

* fix typo

* fix typo in config

* modify INSTALL.md

Update information how to arrange cityscapes data.

* Add cityscapes class names

* Added Registry use for validation datasets (distributed)

* Allowing for default_args for build_dataset

* Using build_dataset instead of build_from_cfg

* Add exceptions handling while validating

* fix lint

* add Exception type

* Add support of the wider face dataset

* Update readme

* Prevent ignoring boxes in test mode

* Rename wider to wider_face

* Rename configs for wider face

* Reformat use yapf 0.27.0

* Add yapf style file