Amending Title 14 of The Philadelphia Code, entitled "Zoning and Planning," by adding a new Chapter providing for the creation of Neighborhood Residential Preservation and Revitalization Overlay Districts; providing for the adoption of design guidelines for properties within such Districts; and requiring special permits to alter the exterior of a building within such a District or to construct a building within such a District so as to ensure compliance with the design guidelines; all under certain terms and conditions. — Open Common Ground