Martin Scorcese’s Gangs of New York could be the most important movie released this year. Here’s why: Time was (back in the 70s) that directors were the main push behind what movies got made. Nowadays, a small number of A-list actors seems to call the shots. Scorcese’s $100-million Gangs is a director-driven project, and despite its long messy birth, if it sells, directors may get back some of the influence over what gets made…