In three short years with the Drive-By Truckers, the Georgia-based southern-rock stalwarts, Alabama native Jason Isbell was a model of efficiency: The eight songs he wrote for them, over the course of three albums, are among the group's finest tracks. (I would argue Isbell's Outfit is the best song they ever did.) Last night at Raleigh's Lincoln Theatre, Isbell--who now fronts his own group, the