This PR adds a download link to all examples in the documentation
(that are included via the examples extension). I think we should do
this, as we have text like "download the example here" at several
places already...
The way expert-only options have been rendered in the documentation emphasized those options, which is exactly what should not be done. This PR changes the rendering to make those options slightly opaque instead.
This PR adds documentation for api::Statistics and api::Stat, as well as further explanations in sphinx.
It also adds a custom css to our sphinx theme that slightly changes how inline code blocks look.
