While it’s sad to say goodbye to wisecracking US Marshal Raylan Givens (Timothy Olyphant), the drama’s sixth and final season (previously shown on Sky On Demand) is an utter treat, with the likes of Sam Elliott, Mary Steenburgen and a splendidly sinister Garret Dillahunt having a ball as guest stars. Tonight, Raylan’s nemesis, eloquent criminal Boyd Crowder (Walton Goggins), is plotting an audacious bank heist…