Publish Documentation

Have local geomesa (path in $GEOMESA) and geomesa.github.io (path in $GEOMESA_GITHUB_IO) source repositories
Have Python and Sphinx set up as described in $GEOMESA/docs/README.md

Check out the release and create a backports branch:

$ cd $GEOMESA
$ git checkout geomesa_2.11-1.3.1
$ git checkout -b docs_131_backports
$ git push --set-upstream ccri docs_131_backports

Update the local geomesa.github.io repo:

$ cd $GEOMESA_GITHUB_IO
$ git checkout master
$ git fetch --prune
$ git pull

Run the $GEOMESA/docs/bin/build-and-mirror.sh script to build and mirror the docs, both the "root" docs at http://geomesa.org/documentation/ and the version-specific branch at http://geomesa.org/documentation/1.3.1/ (or whatever version you are working with).
```
$ ./build-and-mirror.sh --gm $GEOMESA --gmweb $GEOMESA_GITHUB_IO docs_131_backports 1.3.1
$ ./build-and-mirror.sh --gm $GEOMESA --gmweb $GEOMESA_GITHUB_IO docs_131_backports root
```
Edit _includes/header.html in order to add links to the previous version's documentation in the drop down.
Update and commit the version numbers to the webpage by editing the stable and development versions here: https://github.com/geomesa/geomesa.github.io/blob/master/_config.yml
(Optional) Add an entry to the "News" section on the main page to announce the new release.
Check that everything copied to $GEOMESA_GITHUB_IO properly (jekyll serve --watch and go to http://localhost:4000/documentation/ if you have set that up)

Add and push the updated website:

$ cd $GEOMESA_GITHUB_IO
$ git add --all documentation
$ git commit -m "Updating docs for 1.3.1"
$ git push

Run the 'snapshot/nightly' documentation build job here: http://jenkins.ccri.com:8080/job/geomesa_docs_master/.