(svn r2256) - Fix: Trains cannot find a depot when they are in a tunnel. (glx)

- Add: GetVehicleTrackdir() helper function.
- Codechange: Moved SortStruct from vehicle_gui.h to ttd.h, so the dependency from vehicle.h on vehicle_gui.h could be removed.
- Codechange: Typedeffed the VehicleTypes struct so it can be used as the type for Vehicle.type instead of "byte".
- Codechange: Removed prototype for VehicleSorter(), which had no implementation anymore and was never called.

network_server.c

@@ -1291,6 +1291,9 @@ void NetworkPopulateCompanyInfo(void)
 				case VEH_Ship:
 					_network_player_info[v->owner].num_vehicle[4]++;
 					break;
+				case VEH_Special:
+				case VEH_Disaster:
+					break;
 			}
 	}