Updates to the notes/dump-load-format.txt document

This is a heads-up that because of my work on reposurgeon I have begun
doing some minor updates to notes/dump-load-format.txt to keep it
current with my understanding of Subversion's dump behavior. I expect
these to continue sporadically over the next month.

As usual, I do not contemplate making any code changes at all.

Should this material move to the design wiki?

-- 
		Eric S. Raymond
The American Republic will endure, until politicians realize they can
bribe the people with their own money.
	-- Alexis de Tocqueville