"Stronger " is about a survivor but it is not a feel-good movie. In 2013, 27-year-old Jeff Bauman went to watch his ex-girlfriend, Erin Hurley, run the Boston Marathon. He was there when the bombs went off and lost both of his legs as a result. An Associated Press photograph of Bauman, bloodied and gravely injured, being wheeled away from the site by a man in a cowboy hat became an instant icon of that terrorist attack. But the attack is not the focus here. It's the story of the aftermath that director David Gordon Green tells in "Stronger," based on Bauman's co-written memoir, and it is raw, ugly and painful to watch at times.