For some reason I've been sorting lots of TODOs recently, and found the
default behavior of org-sort-entries a little odd. It sorts according to
the order found in org-todo-keywords-1, which apparently just comes from
the order the keywords were scanned during setup. I don't think that's
all that useful, so the attached patch sorts first by
org-not-done-keywords vs org-done-keywords, then alphabetically.
Headings with no keywords sort "big".

I'm not very experienced at logical tricks like sorting strategies, and
I'd be very curious to see if anyone had a more concise way of
expressing the comp function.

Eric