EXCLUSIVE :   John Gore the Broadway maven turned fledgling movie mogul is making his first foray into the Cannes market today with a new film about Wallis Simpson , the woman for whom a king gave up his throne, and he was determined that the grand royal title of Duchess “had better be in its title.” One early runner was  The Bitter End  but Gore dismissed it, because he  felt that the film starring  Dame Joan Collins and Isabella Rossellini should feature a royal salutation in its name. What’s in a name is important, and certain movie titles “get so much penetration,” Gore attests. Watch on Deadline Eventually, after tiring of  The Duchess & I,   The Duchess & Me  and other similar names, the filmmakers decided to go with  My Duchess .…