Timetable: Implement autofill/automate for taken conditional orders.

Fix wrong timetable values being set after using skip or send to depot.
Add timetabled flag for conditional order branch taken travel time.

src/vehicle.cpp

@@ -2892,6 +2892,9 @@ CommandCost Vehicle::SendToDepot(DoCommandFlag flags, DepotCommand command, Tile
 				this->current_order.MakeDummy();
 				SetWindowWidgetDirty(WC_VEHICLE_VIEW, this->index, WID_VV_START_STOP);
 			}
+
+			/* prevent any attempt to update timetable for current order, as actual travel time will be incorrect due to depot command */
+			this->cur_timetable_order_index = INVALID_VEH_ORDER_ID;
 		}
 		return CommandCost();
 	}