Jason Isbell and the 400 Unit rolled into Asheville, NC last night and finished their show with a debut of the Allman Brothers’ “Whipping Post,” possibly a better-late-than-never tribute to the late Gregg Allman. Isbell has previously praised the Allman Brothers, talking to Relix about his connection to the Brothers via FAME Studios which famously housed Duane Allman in his early days. He…