NORTH ANDOVER (MA)— Town leaders learned the hard way this week: Don't mess with Christmas. Five days after the town ordered firefighters to take down their decades-old Merry Christmas sign from the fire station, they got the OK to hang it back up yesterday afternoon. "It seems like a happy ending," North Andover fire Chief William Martineau said, smiling as people drove by slowly, beeping and yelling out Merry Christmas. "It put a little joy back in the holidays." The controversy had people across the country talking about North Andover. Town Hall was flooded with angry phone calls this week....