Rename sidebar.css to markdown-sidebar.css
Start testing and developing a sidebar layout. This is currently just a basic copy of bootstrap's "basic sidebar" template currently.
Work on the sidebar layout. Also, rename layout.html to simple-layout.html.

This also updates a few other things, like static_serve now uses the filename without the '.html' as the endpoint for static templates, and removing the Arbutus from the index title.
Update 403 message to be more correct.
Update markdown documentation serving to be a lot more robust for paths, and also include a 'project not found' page.
This also renamse markdown_serv to documentation_serve and github_pull to documentation_update