FYI: ChangeLog rotation

[Tom Tromey]

FYI, I'm moving all the 2004 ChangeLog entries to ChangeLog-2004.
I'm not posting a patch as it is large-ish and completely
uninteresting.

Just as a reminder, please update the copyright headers in files as
you modify them.  If you use Emacs, you can easily have it do this for
you (with the caveat that there is a known bug for multi-line
copyrights).

Tom