Log Message:
-----------
Minor improvements to the TODO list. Add some URLs for some
existing TODO items, and re-add a TODO item for an "estimated
count" capability.
Modified Files:
--------------
pgsql/doc:
TODO (r1.2040 -> r1.2041)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.2040&r2=1.2041)