= site: add OpenSearch "search" and suggestions plugin for easy documentation access

If you know it is there you can configure your browser to search the spray 1.2.0 documentation directly from the search box.

See http://pc.blog.zemows.org/2013/04/26/opensearch/ for how to configure your browser. An on-page search box would be nice, too, but I didn't figure out how to place the search box into the page without the layout breaking.