Idea: entries in UPDATING for each release

[Warren Block]

Right now, people who install ports from a -release CD and then start 
upgrading don't have a clear marker for how far back to go in UPDATING.

A simple entry would be enough:

   20100703:
     AFFECTS:
     AUTHOR:

     FreeBSD 8.1-RELEASE

Not sure what AFFECTS should say.  There might be other useful 
information that could be included in the note.  Comments?