Krispy Kreme Doughnuts extends National Coffee Day celebration with a free cup of coffee from Friday, Sept. 29-Sunday, Oct. 1   WINSTON-SALEM, N.C., 2017-Sep-22 — /EPR Retail News/ — Krispy Kreme Doughnuts announced that it will spread the joy of National Coffee Day over an entire weekend, offering guests one free cup of coffee each day, Friday,…