Midway through the first period, Nathan Horton could sense that the Florida Panthers would soon end their problems in Atlanta. “We hadn’t won here for I don’t know how long,” he said. “That’s why it was so good to win here tonight.” Horton scored two goals for the first time since last March to help Florida Panthers beat the Thrashers 5-3 on Thursday night and end an 11-game winless streak in…