Rename/convert NEWS to NEWS.md No meaning in keeping RST (and, even more, half-RST/half-MD) around when for this Markdown is enough. Also ship SECURITY.MD in the sdist.
Store doc/readme and doc/news in git … instead of always re-creating them. This is in an attempt to make readthedocs work, since it can't run builds, I think.
Remove doc/news.rst from git Forgot to do this when changed readme. It is now symlinked at build time.
Reorganise documentation Lots of changes so that all docs are buildable by Sphinx.