It definitely helps to give your protagonist a certain “set of skills,” particularly if he is played by that grand master of icy revenge, Liam Neeson. Neeson, impossibly craggy yet as ruggedly handsome as ever, stars in the new film “The Marksman” as Jim, a widowered Arizona rancher with a history in the armed forces and a rather keen eye with a rifle scope—hence the title. Jim’s ranch abuts the Mexican border, and during one of his daily rounds he comes upon injured migrant Rosa