Dennis O’Mara, the Glen Arbor Art Association artist-in-residence (AIR) May 18-31, talks about his two-week stay Thursday, May 29, 7:30 p.m. at the GAAA, 6031 S. Lake St., Glen Arbor.   O’Mara, a Hastings, Michigan, resident, works in many media – from pastel to oil, linoleum cut to cast paper – and is at work