Throughout a career spanning more than 30 years, John Martinelli remained one of television’s most valued editors — from his first solo credit on “Gentle Ben” to such 1980s mini-series as “Marco Polo” and “A.D. – Anno Domini.” “Editors were trusted more back then,” he says. “They had the first cut before the director. With all those film cans lying around in the editing room, it was a mystery to anyone but the editor on where to begin.”Martinelli’s roots in the film editing profession run deep — deep enough to remember, as a child, watching his father splice several Roy Rogers projects at Paramount Laboratories. His uncle Arthur, meanwhile, was one of Hollywood’s first cinematographers during the silent era.