docs: Host docs for all stable library versions #30
Description
Documentation hosted on https://readthedocs.org/ is frequently available for all stable library versions. I'd like to do the same for this one, but I decided not to go with Read the Docs for now. A similar thing should be possible with sphinxcontrib-versioning. This is not a priority now that it's recommended that users stay up to date with the master branch, but once v0.3 is released and the library continues to evolve further, this should be considered.