Hedwig and the Angry Inch, Belasco Theatre, May 21; An American in Paris, Palace Theatre, May 22; The Two Gentlemen of Verona, Polonsky Shakespeare Centre, Brooklyn, May 23 (matinee); The Flick, Barrow Street Theatre, May 24 IS there a more gallant, a more scintillating, a more lovable character on Broadway right now than Hedwig, in the person of…