Nothing contained in this part and part 3 of this chapter shall be deemed to supplant or modify the provisions of any special or private act relating to the zoning or zoning powers of any municipality referred to in such special or private act, and all the provisions of such special or private act shall remain in full force and effect, but insofar as this part and part 3 of this chapter are not inconsistent with the provisions of such special or private act, this part and part 3 of this chapter shall apply to the zoning powers and procedure of such municipality.