What’s this, what’s this? “The Nightmare Before Christmas” is coming to theLady Bird Johnson Wildflower Center this fall, so everybody scream. Disney’s “Tim Burton’s The Nightmare Before Christmas” Light Trail will allow visitors to travel between Halloween Town and Christmas Town in a world unlike anything you’ve ever seen. The nighttime trail will be open dusk to 10:15 p.m., Wednesdays-Sundays, fromThursday, Sept. 25 to Sunday, Nov. 30…