Focus on search box

[burodepeper]

The default installation for mkdocs had the auto focus on the search input field, so I copied the base.js to the cinder directory, and I'm kind of assuming here that this will work. Let me put it this way: as long as you haven't modified any of the html or css, I'm not really sure why this won't work... ; )

[anlau]

@chrissimpkins, could you elaborate on why this PR was closed?

This behaviour can probably be introduced using extra_javascript, but I think it should be part of the theme (like it is with MkDocs default theme).

I can open a PR with lines 25-27.

Thanks

[chrissimpkins]

There was a refactor of the theme here with the release of MkDocs v1.0 and I believe this was closed when that took place. I am not opposed to including the functionality but we need to make sure that the JS change works as expected.