San Francisco Chronicle: The Board of Supervisors voted 9-2 Tuesday to approve Mayor Gavin Newsom’s proposal for the most comprehensive mandatory composting and recycling law in the country. It’s an aggressive push to cut greenhouse gas emissions and have the city sending nothing to landfills or incinerators by 2020. “San Francisco has the best recycling and composting programs in the nation,” Newsom said, praising the board’s vote on a plan that some residents had decried as heavy-handed and impractical. “We …