Section 511 - Authority of municipality; other terms of contract1. Any municipality is authorized to enter into agreement with the state to receive such loans, periodic subsidies and state capital grants to assist such municipality to establish and carry out one or more programs of urban renewal.2. In the case of a loan, the loan contract shall provide that upon any date when an installment of principal shall become due and payable the municipality may anticipate any installment which would otherwise become due and payable thereafter.3. In every contract for a loan and periodic subsidy or for a capital grant by the state, the acts constituting a substantial breach of the provisions set forth therein shall be defined in such terms as the commissioner shall deem to be in the public interest and as are consistent with the provisions of this article and the purposes of the program for which such aid is sought. In any loan contract, the commissioner shall retain the right, among other rights and remedies, in the event of such substantial breach, to declare any unpaid balance to be due forthwith and to reduce or terminate any periodic subsidies payable under the contract.4. Every such contract may contain such other terms, covenants and conditions as shall be agreed upon and as are consistent with the provisions of this article and the purposes of the urban renewal program.