Subject to the provisions of Section 2 hereof, any governmental unit, pursuant to laws heretofore or hereafter adopted by the General Assembly, may issue revenue bonds for the purpose of financing all or a portion of the costs of capital improvements of a public nature, facilities for the securing and developing of industry or agriculture, and for such other public purposes as may be authorized by the General Assembly. Such bonds may bear such terms, be issued in such manner, and be subject to such conditions, all as may be authorized by the General Assembly; and the General Assembly may, but shall not be required to, condition the issuance of such bonds upon an election.