John Heller, Oneonta • 1980-2018 FIREMAN DIES A HERO By: Libby Cudmore ONEONTA The former Oneonta firefighter made sure his four nephews, Donovan, 9, John Heller died a hero. Maddox, 7, Macall, 5 and Rawley, 2, as well as his fiancée, Amber Roe, were safe when an early-morning fire broke out in his 5 Walling Ave. home on Saturday, Dec. 29. “He and Amber are my heroes,” his sister-in-law, Erika Heller, wrote in an emotional Facebook tribute. “They saved my…