The bonds authorized by this article and the income therefrom, all trust indentures and mortgages executed as security therefor, all loan agreements (including agreements of lease) made pursuant to the provisions hereof, and the revenues derived from any loan agreement thereof shall be exempt from all taxation in the State of South Carolina except for inheritance, estate or transfer taxes; and all trust indentures, mortgages and loan agreements made pursuant to the provisions of this article shall be exempt from South Carolina stamp and transfer taxes.