[Exim] headers cleanup

In case others are also bored by the excess of useless headers (a
sort of package-junk) that burdens emails from some sources, may I
remind you of the flexibility of exim:

     headers_remove =
X-Spam-Report:X-Spam-Score:X-Spam-Score-Int:X-XPoint-AntiAbuse

in your local (and virtual domains) routers. I am not happy removing
headers, but since I received emails from the list with the same
amount of extra headers and original content, I think this is
justified.
(Now I wonder if also "signature" headers are easily recognisable)

Giuliano