A steady stream of voters cast ballots in Portland on Tuesday, drawn to the polls by a high-profile mayoral race and two contentious referendum questions. Polls remain open until 8 p.m. Elections workers at East End Community School reported a strong, steady turnout throughout the day. At 6 p.m., there was a 20-minute wait for a ballot, with a line snaking around the gymnasium. “That’s pretty dang good for an off-year election,” said Denise Shames, the election official at the East End precinct.