SAN ANTONIO--(BUSINESS WIRE)--CST Brands, Inc. (NYSE: CST), one of the largest independent retailers of motor fuels and convenience merchandise in North America, today reported financial results for the first quarter ended March 31, 2015. Three Months Results “Led by a strong U.S. fuel margin along with continued growth in same store merchandise sales, both in the U.S. and Canada, we delivered solid results for the first quarter of 2015,” said Kim Lubel, Chairman and CEO of CST Brands, Inc. “Th