TODO improvements

I have added descriptions to many TODO items.

I need help with all the items marked with question marks. Please post
your comment and CVS committers are welcome to modify it directly.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073