"World" achievements can not be gained as personal achievements (like Reaver, Pyromancer, ...)

git-svn-id: http://svn.net-core.org/repos/t-engine4@1884 51575b47-30f0-44d4-a5cc-537603b46e54

game/engines/default/engine/interface/WorldAchievements.lua

@@ -79,6 +79,10 @@ end
 -- @param src who did it
 function _M:gainPersonalAchievement(silent, id, src, ...)
 	local a = self.achiev_defs[id]
+
+	-- World achievements can not be gained multiple times
+	if a.mode == "world" then return end
+
 	if src.resolveSource then src = src:resolveSource() end
 
 	src.achievements = src.achievements or {}