Everyone knows about the punk scene. In the mid-1970s, rebellious musicians — or even those with no musical talent at all — created a new sound out of their anger and aggression. But that movement didn’t just lead to a new subgenre of music. Creative types of all stripes felt things fall apart. In New York, filmmakers, actors and other artists used those feelings to fuel collaborations that led to modern independent film. “Blank City” tells the story of those who paved the road later traveled by directors such as Jim Jarmusch, Steven Soderbergh, Vincent Gallo and Steve Buscemi.