Low-key and lovely, the independent movie “Cold Weather” opens with a shot of raindrops clinging to a pane of glass, a fitting introduction for a movie about characters who are revealed gradually, as if through a glass — not darkly, but obliquely. With brooding, expressive digital photography, a rooted sense of place and characters that seem as real as the people next door, the director Aaron Katz has created a lived-in world that’s so intimate and familiar that even with the story’s unexpected turns, you might not initially see its art for its everydayness.