* update pre-commit hook config

* fix styles conflicting with pre-commit hooks

* 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

* update code

* reformat

* fix load pretrain bug

* reformat

* fix key warnings

* use build_conv_layer & ConvModule

* rm unrelated file

* fix resnext group bug

* change cfg to pass test

* use build_conv_layer to claim dcn in resnets

* change _version = 2

* MDCN to DCNv2

* change dependency of mmcv from 0.2.15 to 0.2.16

* resolve comments

* rm comments

* get_root_logger()

* Albumentations wrapper

* 2 single quote format

* version >= 0.3.2

* add testing in Travis

* add proj. requirements

* install CUDA

* def tested packages

* add missing meta in setup

* add empty test

* restructure travis tests

* add sample doctest

* switch to nose2

* add sample test

* using pytest

* minor fixes