“I wanted to be the funny one,” laments the title character of “Hannah Takes the Stairs,” “and I’m never the funny one.” That’s not true. As played by the actress-writer Greta Gerwig, Hannah is neurotic, sweet and mildly sarcastic, in a Gen Y-Diane Keaton sort of way, and her small-stakes odyssey through three relationships is wryly observed. That said, “Hannah,” the third feature by the Chicago writer-director-editor Joe Swanberg, i find out more...