Repeal of “An Act in relation to the creation of public library districts”, approved May 16, 1957, and repeal of the Illinois Public Library District Act shall not abrogate any referendum held under either of those Acts, but the referendum shall be given full effect as if conducted under this Act. Nor shall the repeal of those Acts abrogate any bonds issued under either repealed law, but those bonds shall continue to be deemed as a valid bond issue and legally binding upon the district having sold the bonds, and the district may continue to levy the taxes necessary and sufficient to pay the principal of and interest upon those bonds under this Act.