* Vendor parts of the Docker SDK for Python
This is a combination of the latest git version
(db7f8b8bb6)
with some fixes to make it compatible with Python 2.7
and adjusting some imports.
* Polishing.
* Fix bug that prevents contexts to be found when no Docker config file is present.
Ref: https://github.com/docker/docker-py/issues/3190
* Linting.
* Fix typos.
* Adjust more to behavior of Docker CLI.
* Add first iteration of docker_context_info module.
* Improvements.
* Add basic CI.
* Add caveat on contexts[].config result.