Contact info / authors / change history for the desktop file spec

[Owen Taylor]

It would be good to:

 - Include information about where feedback on the   
   desktop spec should go (xdg-list for now, though
   possibly bugzilla long term)
 - Correct the authors to indicate all contributors,
   and maybe remove the email addresses.
 - Add some sort of change history to the desktop file spec

People are still mailing the authors list, which does
no good ... I haven't touched it in a couple of years,
and Preston and Jonathan longer.

Regards,
					Owen