Make the list of available versions dynamic. The items displayed is now
generated with javascript. The parent directory of the site is supposed
to contain versions.js providing getVersionListItems() that returns the
available versions.
The update-gh-pages.sh script is modified to update/create versions.js
on every invocation. It simply lists all directories in the root
directory and adds them to the version list.
Sync our customizations under _includes/ with v2.0.9 of
jekyll-rtd-theme. Also, pin the theme version in order to avoid abrupt
build failures in the future (caused by our customization becoming
incompatible with the rolling latest version).
Also, drop jekyll-rtd-theme from the Gemfile. It's useless there as it's
being mandated by remote-theme setting in _config.yml.
Add rules for building and serving the html documentation inside a
container.
- 'make site-build' will build the html content unders docs/_site.
- 'make site-serve' builds the site content and serves it at
http://localhost:4000/
