[Freeciv-Dev] event messages fixes

[David Pfitzner <dwp@xxxxxxxxxxxxxx>]

This patch (to very current cvs) fixes a few annoyances with event 
messages and the messages window.

Once upon a time Michael Bickel submitted a patch to reduce excess
"city needs Aqueduct" messages, by supressing the message if the city
is already building an Aqueduct.  I was concerned about possible bad
effects, but never got around to doing a better fix.  This patch 
implements the functionality of Michael's patch by having the server
send a different event type if the city is alreadying building.
Then the client can filter (or not) based on the event types, and 
hopefully everyone is happy.

Other fixes are to reduce cases of the messages window popping up 
"interactively" (and I find annoyingly) when a player does something 
like sell an improvement or make an attack.  (Partly by adding some 
new event types, and defaulting some event types to "output window 
only".)  For consistency (and also to keep an even number of messages 
-- which looks better in the options dialog :-) I also adjusted the 
diplomacy messages similarly: different types for diplomacy "attacks"
and "defenses" messages.

-- David

event_fixes1.diff.gz
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