Photo: Brant Ward / Brant Ward / The Chronicle 2014 Image 1of/1 CaptionClose Image 1 of 1 Buy photo San Francisco's Yellow Cab Co-op has been sold to a competitor for less than a million dollars. San Francisco's Yellow Cab Co-op has been sold to a competitor for less than a million dollars. Photo: Brant Ward / Brant Ward / The Chronicle 2014 Buy this...