Fix sound stuttering where large tile numbers were used in route, by normalizing all sound world coordinates to camera tile. Fix candidate for wrong rolloff calculation in case high number were set for deactivation distance.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@1849 a9f3cfff-6c41-7446-b0ca-052bd761e6eb