Factored out boilerplate from all html docs in doc directory:
- the first HTML comment in those files is extracted as page
title when serving them
- lib/godoc.html is top-level template for all pages served
- experimented a bit with package documentation layout
(feedback welcome)
- various related cleanups
TODO:
- The / page (doc/root.html) content repeats links that are
in the navigation bar. It needs to be cleaned up.