Seattle, 2016-Aug-03 — /EPR Retail News/ — This year's country breakthrough artist and Grammy Award-winner Chris Stapleton is the latest to step in as a Guest DJ for Starbucks and take his turn selecting songs to be played in the company's U.S. stores today (July 29). Stapleton's two-hour playlist is an eclectic mix of country, Americana, roots and soul. The Starbucks…