Unless a contrary intention appears by the will, a bequest of the estate of the testator shall be construed to include any property which he may have power to appoint by will to any object he may think proper, and shall operate as an execution of such power; and a bequest of property described in a general manner shall be construed to include any property to which such description may extend, which he may have power to appoint by will to any object he may think proper, and shall operate as an execution of such power.