(svn r165) -Feature: Option to sort vehicles in vehicle-list window by different criteria. Total independent sort for all types and players. Periodic resort of list every 10 TTD days. Thank you for your graphical inspiration follow and buxo (since none of you provided any code).

-Fix: Sorter icon pointing down 'v' sorts in every window lowest value first, '^' highest value first
-CodeChange: move Dropdownlist from settings_gui.c to widget.c. More in place there.

vehicle.h

@@ -1,6 +1,8 @@
 #ifndef VEHICLE_H
 #define VEHICLE_H
 
+#include "vehicle_gui.h"
+
 typedef struct VehicleRail {
 	uint16 last_speed;		// NOSAVE: only used in UI
 	uint16 crash_anim_pos;
@@ -369,6 +371,7 @@ byte GetDirectionTowards(Vehicle *v, int x, int y);
 #define BEGIN_ENUM_WAGONS(v) do {
 #define END_ENUM_WAGONS(v) } while ( (v=v->next) != NULL);
 
+#define DEREF_VEHICLE(i) (&_vehicles[i])
 #define FOR_ALL_VEHICLES(v) for(v=_vehicles; v != endof(_vehicles); v++)
 
 /* vehicle.c */