Caron Butler's 16-foot jumper had no chance. Shawn Marion was all but guaranteed to get a hand on it. The Washington Wizards aren't having much of a season, and the Dallas Mavericks don't lose when it's a one-point game. Marion blocked Butler's shot with 1.9 seconds to play Wednesday night, and the Mavericks opened the second half of their season by avenging a loss from opening…