Whoopi Goldberg pays long overdue tribute to a pioneering figure in the history of comedy, Moms Mabley in a new documentary premiering on HBO tonight.  In an era where stand-up comedy was almost entirely white and male and — as far as anyone knew — straight, she was a very successful gay black woman, first on “the chitlin’ circuit” of black theaters and clubs and then in more mainstream venues.  But Mabley was anything but mainstream.  She played Carnegie Hall and appeared on the Smothers Brothers and other television shows.  She appeared on stage as a bedraggled, toothless, soul, which helped disguise the sly sharpness of her comedy.  I hope Goldberg’s documentary will bring her the recognition she deserves and create a new generation of fans.