Adds a docker container for doing dev which runs as part of the `devstack_default` network and is accessible with the hostname `edx.devstack.blockstore` from devstack containers.
Add CircleCI config with tests and quality jobs.
Adds `diff-cover`. On CircleCI the coverage details can be seen in tests logs.
Updates commands in Makefile.
Adds description and dev setup details in README.
Changes `pep8` to `pycodestyle`.
Fixes all quality issues.
Verify that the tests and quality jobs run on CircleCI.
Verify the the docker container is setup correctly and can be accessed from devstack containers.
Verify diff-cover is logged correctly.
Verify the make commands all run correctly.
The last commit has been added to test the quality job. It will be removed before merging.