WESTBROOK — A crowd of more than 100 people, including at least two who were carrying handguns, came out to a candlelight vigil on Tuesday night in memory of 19-year-old Treyjon Arsenault, who was fatally shot Monday night in Portland. The crowd, made up mostly of Arsenault’s friends and acquaintances about his age, lit candles on a public basketball court off Main Street in downtown Westbrook where Arsenault was a regular.