Doc cleanup

Probably not ready to merge.

I would like feed back on most of this.
Because sphinx errors told me the file does not exist
On Jun 12, 2014 6:58 AM, "Phil Elson" <notifications@github.com> wrote:

> In doc/api/index_backend_api.rst:
>
> > @@ -9,6 +9,6 @@ backends
> >     backend_qt4agg_api.rst
> >     backend_wxagg_api.rst
> >     backend_pdf_api.rst
> > -   backend_webagg.rst
> > +..   backend_webagg.rst
>
> Why comment it out?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/matplotlib/matplotlib/pull/3133/files#r13699574>.
>