“Smithereens” (1982), directed by Susan Seidelman. 90 minutes. No rating. In the spirit of the punk movement that inspired it, this film spews raw spontaneity, stars a mostly non-professional cast and looks like it was made for a few thousand dollars. It focuses on Wren, a hyper, just-out-of-high-school Jersey girl trying to be a part of the New York punk scene, and a band called Smithereens (a name used later by a real-life pop band).