Zzzeek's Sphinx layout and utilities

 This layout is first and foremost pulled in for the SQLAlchemy documentation
 builds (and possibly other related projects), but is also usable as a
 standalone theme / utility set for any project.
 .
 Features include:
 .
  * uses Mako templates instead of Jinja, for more programmatic capabilities
    inside of templates
  * layout includes an independently scrollable sidebar
  * unique (to Sphinx) “contextual” sidebar contents that shows the current
    page in context with all sibling pages
  * modifications to autodoc which illustrate inherited classes, bases, method
    documentation illustrates if a method is only inherited from the base or
    overridden
  * “dynamic base” feature that will, under ReadTheDocs, pull in optional
    .mako and .py files from the website of your choice that will serve as an
    alternate base template and a source of extra config setup, respectively,
    allowing the layout to be integrated into the layout of an external site
    when viewing on the web
  * “viewsource” extension that can provide highlighted sourcecode to any
    Python file arbitrarily
  * SQLAlchemy-specific stuff, like the [SQL] popups, the dialect info
    directives
  * scss support using libsass