The mood is melancholy, the road ahead unclear. Which may explain the slew of biographical and autobiographical novels and films in a meandering Proustian fashion that go for the past. And, just like Proust’s oeuvre, never boring but intriguing and beguiling at the same time. After the Norwegian Karl Ove Knausgaard’s six-volume memoir, “My Struggle,” the gorgeous Mike Mills film, “20th Century Women.” I hadn’t seen “Beginners”