the four-part HBO documentary chronicling the doomed marriage and contentious custody battle between Woody Allen and Mia Farrow, is causing legal trouble in its own right — over copyrights. Skyhorse Publishing, which released Allen’s latest book, “Apropos of Nothing,” is threatening to sue the makers of the buzzy and controversial show for sampling bits from the famous director’s audiobook. Allen, 85, did not participate in the show, which premiered Feb.