Voters in the District and Maryland overwhelmed election officials at several polling places Saturday when larger than expected crowds turned out on the first day of early voting to cast ballots. Officials said thousands showed up at voting sites, spurred on by President’s Obama plea to vote early — and concern about the threat posed by Hurricane Sandy. Several polling officials found themselves in a midday scramble to install more voting machines. Long lines and lengthy waits were reported at polling places in Montgomery and Prince George’s counties, as well as in several of the District’s wards. Some voters, frustrated...