rework of world altitude calculation.

src/engine/server/world/WorldServer.java

@@ -566,8 +566,7 @@ public class WorldServer {
 		for (Zone zone : rootParent) {
 
 			ZoneManager.addZone(zone.getLoadNum(), zone);
-			zone.generateWorldAltitude();
-
+			zone.worldAltitude = ZoneManager.caclulateWorldAltitude(zone);
 
 			//Handle Buildings