GWEN ANSELL MUCH will be written about the music career of Sibongile Khumalo and many will elide her achievements into the single, limited category of “singer”. Singer she was, no doubt, and a magnificent one, with a voice that melded honey, smoke and crystalline waters into a cascade of captivating sound. She resisted, throughout her career, the genre envelopes into which critics tried to stuff her. She did not set out to be an “opera singer” or a “jazz singer” and did not appreciate media coverage that tried to confine her within one of those boxes and assess her work…