Bill’s got his groove back

Bill Callahan’s recent album Shepherd in a Sheepskin Vest (Drag City) contains the singer-songwriter’s first set of new songs in six years. That’s a long time for a guy who made 15 LPs in the 23 years between Sewn to the Sea, his first full-length as Smog, and Dream River, which came out in 2013 (followed by a dub companion, Have Fun With God, the next year).…