Add order management dropdown, add duplicate order and move jump target

Add setting to control if order management button shown

Move order list management to order management dropdown if enabled

See: #439

src/command_type.h

@@ -288,6 +288,7 @@ enum Commands {
 	CMD_SKIP_TO_ORDER,                ///< skip an order to the next of specific one
 	CMD_DELETE_ORDER,                 ///< delete an order
 	CMD_INSERT_ORDER,                 ///< insert a new order
+	CMD_DUPLICATE_ORDER,              ///< duplicate an order
 	CMD_MASS_CHANGE_ORDER,            ///< mass change the target of an order
 
 	CMD_CHANGE_SERVICE_INT,           ///< change the server interval of a vehicle