docs/: restructure so that common stuff is shown first

docs/: restructure so that common stuff is shown first

Original commit message from CVS:
* docs/Makefile.am:
* docs/manual/elements-api.xml:
restructure so that common stuff is shown first
* docs/manual/init-api.xml:
convert to examples
* docs/manual/manual.xml:
* docs/manuals.mak:
* docs/url.entities:
link to API on the website, possibly override later in build
* examples/manual/.cvsignore:
ignore more
* examples/manual/Makefile.am:
add more examples
* examples/manual/extract.pl:
error out on failure