Multiple intros cause trouble since they have some section elements
(e.g. "y2k.sgml") in common leading to duplicate labels.
Include emacs formatting hints in the intro*.sgml sources.
Split introduction sections into separate files to allow the legal notice
and notation sections appear in all documents without having the history
show up everplace too.
Add full list of reserved and non-reserved key words in syntax.sgml.
Add a separate chapter to the admin guide on security.