docs for 408 - direction suffixes.  Fixes #454

This *deliberately* does not include the gh-pages files as they should be regenned on a system that is set up to use the same theme (I had to use default instead of the sphinx_rtd_theme, and thus ended up changing every file).

maybe better:

if html_theme == 'sphinx_rtd_theme':
    import shinx_rtd_theme
    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]