- Fix the html/install removal for "make clean"
- Fix test of "userguide" when making links
- Make must fail when openjade fails. Testing doc/book1.htm is not
enough, for example when you have partial docbook installation.
Build install.tgz documentation when DOCBOOK_DSL is defined, as
advertised by the comments.
Clean up unused html/dist/man targets
new clean-local target to remove tmp & html files