General cleanup for 7.0.

against the sources from one hour ago and contain all the portable and
up
to date stuff.

A few other CVS "householding" things you might want to take care of:

* Remove the src/bin/cleardbdir directory

* Remove the file src/bin/psql/sql_help.h from the repository, as it is
a derived file and is build by the release_prep.

Peter Eisentraut

A few other changes, but I forget what :(

Use a <citetitle> rather than <xref> when referring to libpq
 since that chapter is not included in the tutorial.

Fix Id tag in chapter headings to allow meaningful file names in html.