Suggest C-x 4 a skip initial copyright

[Kevin Ryde]

In GNU Emacs 20.5.2 (i386-debian-linux-gnu, X toolkit)
 of Wed Dec 29 1999 on raven
configured using `configure  i386-debian-linux-gnu --prefix=/usr 
--sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib 
--infodir=/usr/info --with-pop=yes --with-x=yes --with-x-toolkit=yes'

I think it'd be useful if add-change-log-entry were to recognise and
skip an initial copyright notice in a changelog file.

I know it's recommended in the gnu maintainer info to have a copyright
statement at the end of the file, but that seems to me to obscure it
to the point of near invisibility and that emacs could help to have it
at the top instead.

I see there's a "(goto-char (point-min))" in add-change-log-entry.
Perhaps that might merely need to become a search for the first line
starting with a date like "2001-09-28".  I guess that date format is
configurable, so maybe the matching would have to be too.  Perhaps a
separator line like "----------" would be more general or reliable.

For what it's worth I get some joy from narrowing the buffer (either
in a local variables "eval:" or in change-log-mode-hook) to trick that
goto-char, but no doubt it's better not to narrow but just to skip.