Merge tag '14.0-beta2' into jgrpp

# Conflicts:
#	CMakeLists.txt
#	src/cargotype.cpp
#	src/console_cmds.cpp
#	src/graph_gui.cpp
#	src/industry_cmd.cpp
#	src/industrytype.h
#	src/misc_gui.cpp
#	src/network/network_client.cpp
#	src/newgrf.cpp
#	src/newgrf_town.cpp
#	src/object_cmd.cpp
#	src/openttd.cpp
#	src/pathfinder/water_regions.cpp
#	src/saveload/saveload.cpp
#	src/saveload/saveload.h
#	src/table/build_industry.h
#	src/table/engines.h
#	src/vehicle.cpp
#	src/vehicle_cmd.cpp
#	src/vehicle_gui.cpp

src/vehicle_cmd.cpp

@@ -178,7 +178,8 @@ CommandCost CmdBuildVehicle(TileIndex tile, DoCommandFlag flags, uint32_t p1, ui
 				_returned_refit_capacity = e->GetDisplayDefaultCapacity(&_returned_mail_refit_capacity);
 				_returned_vehicle_capacities.Clear();
 				_returned_vehicle_capacities[default_cargo] = _returned_refit_capacity;
-				_returned_vehicle_capacities[CT_MAIL] = _returned_mail_refit_capacity;
+				CargoID mail = GetCargoIDByLabel(CT_MAIL);
+				if (IsValidCargoID(mail)) _returned_vehicle_capacities[mail] = _returned_mail_refit_capacity;
 			}
 		}
 
@@ -438,7 +439,8 @@ static CommandCost RefitVehicle(Vehicle *v, bool only_this, uint8_t num_vehicles
 		total_mail_capacity += mail_capacity;
 
 		_returned_vehicle_capacities[new_cid] += amount;
-		_returned_vehicle_capacities[CT_MAIL] += mail_capacity;
+		CargoID mail = GetCargoIDByLabel(CT_MAIL);
+		if (IsValidCargoID(mail)) _returned_vehicle_capacities[mail] += mail_capacity;
 
 		if (!refittable) continue;