Organize the documentation: readthedocs

[parmentf]

Put the documentation in https://www.readthedocs.org/

I saw a manifest file (not found in ReadTheDocs doc!) there: https://github.com/kermitt2/grobid/blob/master/mkdocs.yml

[parmentf]

Actually, ReadTheDocs can use Sphinx or MkDocs.

[parmentf]

After merging branch readthedocs into master, this is done.

http://ezvis.rtfd.org/ or http://ezvis.readthedocs.org/ (which redirects to http://ezvis.readthedocs.org/en/latest/)