Document the fact that we can have grouped bars
Document the fact that we can have grouped bars

printedheart/jit,tim777z/jit,shelsonjava/jit,shzy2012/jit,mcanthony/jit,printedheart/jit,pingjiang/jit,pingjiang/jit,philogb/jit,shzy2012/jit,philogb/jit,printedheart/jit,pingjiang/jit,mcanthony/jit,tim777z/jit,tim777z/jit,shelsonjava/jit,mcanthony/jit,shzy2012/jit,shelsonjava/jit