ACTION-114 ISSUE-107 : Revised response header.

ACTION-114 ISSUE-107 ISSUE-47 ISSUE-48 ISSUE-51 ISSUE-76 ISSUE-90
ISSUE-106 ISSUE-45

Here is the latest version of the response header. I've also added it to
the action on the tracker.

Editors: it is in markdown, but *do not panic*, any of us can convert it
to HTML at a moment's notice.