* Revise README.md

* Revise `GETTING_STARTED.md`

* Revise `INSTALL.md`

* Add `CONFIG.md`

* Fix RetinaNet backbones in README

* Fix cascade backbones in README

* Fix capitalization

* Replace demo images and update visualize funcall

* Revise `DATA.md`

* Fix link to `DATA.md`

* Fix capitalization