Update to notes/dump-load-format.txt

As promised, I have updated notes/dump-load-format.txt with the
information in the ewplies to my recent query.

I have also added some documentation about special properties and
their formats, notably the RFC3339 format of the timestamps.

The documentation now states that *unless* date properties are
explicitly set or unset, timestamps increases monotonically wituh
revision number. If this is incorrect, simeone please notice and fix
it.

Teo questions have been languishing unanswered in that file sunce
I iriginally wrote it back in 2011.

=== Unresolved questions ===

1. In interpreting a Node record which has both a copyfrom source and
a property section, it is possible that the copy source node itself
has a property section. How are they to be combined?

2. The section on the semantics of kinds of operations documents a
minor bug at r39883 in the behavior of "add". Has this been fixed?

It'd be nice if we could dispose of these.

I will continue to update notes/dump-load-format.txt with the things
that working on reposurgeon requires me to learn.

-- 
		Eric S. Raymond
As war and government prove, insanity is the most contagious of
diseases.	-- Edward Abbey