@tseaver GitHub is not happy about the size of this commit so I will just push from the command line.

For review purposes, to give an idea of how the commits were made:

1. Moving all pages into master subdirectory (b4b226c)

git checkout gh-pages
git mv * master/  # Leaves .nojekyll intact
git commit ...

2. Updating "master" docs with a clean build. (2323c88)

   git checkout master
   # Make change to docs/conf.py as in PR #625
   SPHINX_RELEASE=$(git log -1 --pretty=%h) tox -e docs
   mv docs/_build/html master_DOCs/
   git checkout gh-pages
   git rm -fr master/
   mv master_DOCs/ master/
   git add master/
   git commit ...
   

3. Adding 0.4.0 docs in own folder and in latest. (02c903b)

git checkout v0.4.0
# Change to docs/conf.py from PR #625 not needed
tox -e docs
mv docs/_build/html v0.4.0_DOCs/
git checkout gh-pages
mv v0.4.0_DOCs/ latest/
cp -r latest/ 0.4.0/
git add latest/ 0.4.0/
git commit ...

4. Adding root redirect to the latest docs. (d0713e7)

This one is human reviewable.

I'd say go ahead and merge -- review isn't that feasible. We can tweak later as needed.

Agreed, I wasn't expecting you to be able to review anything other than my methods.

I need to hold off on pushing this until right before #625 gets merged or it will break the build process for merges.

Also, instead of a rebase I'm going to wipe away (git push -f) all the commits since a8df46b.

Merging #625 right after will restore the master docs to the tip of master.

LGTM