Playing out of competition, today’s gala entry, Black Mass, screened for press at an early call this morning with strong applause at the end — twice. Audiences should be cautioned to stick around as there’s a key footnote at the end of the Scott Cooper-helmed crime drama. Johnny Depp has been getting some career best notices for his chameleon-like turn as James “Whitey” Bulger, the notorious leader of Boston’s Winter Hill Gang who is now serving two life sentences for…