Director Shaunek Sen’s new documentary, “All That Breathes,” chronicles the efforts of two brothers, Nadeem and Saud, in Delhi, India, to rescue and care for the bird known as the black kite in their makeshift basement hospital. Although the film is scattered with gorgeous nature shots of soaring birds, frantic ants and slow caterpillars, “All That Breathes” is anything but a nature film: this is a haunting documentary on the complexity and necessity of interspecies coexistence. ...