Montreal Gazette: The mayor of Rosemont-Petite Patrie hopes a new bylaw requiring white roofs on homes and commercial buildings will make his borough the coolest in Montreal -literally. Francois Croteau says his proposed bylaw, which would require all new roofs in the borough to be white -or a colour or material that reflects rather than absorbs heat -makes environmental and economic sense for his constituents. “If in 20 years temperatures in Montreal are much hotter, and we wait until then to …