0.4 draft of new dumpfile documentation

Still working on it as I await restoration of commit access. Here's the
0.4 version. Note the two open questions and the buglet.

Process note: The document is marked up in asciidoc. As a lightweight
format for in-tree documentation, asciidoc is pretty tough to top - easily
read by humans and generates DocBook, so you can get high-quality HTML
out of it. I've moved to it for everything short of book length on my
new projects (but still using DocBook for book length). I recommend that
you guys should seriously consider adopting it for the stuff you're
now carrying in HTML and random plain text.

-- 
		Eric S. Raymond