code: function expandRangeIgnoreCase(ranges) {
    return K.flatten2(ranges.map(function (r) {
      var parts=K.classify([r,'az','AZ']).map[r];
      return K.flatten2(parts.map(function (p) {
        if (/[a-z]/.test(p)) {
          return [p,p.toUpperCase()];
        } else if (/[A-Z]/.test(p)) {
          return [p,p.toLowerCase()];
        } else return [p];
      }));
    }));
  }
docs: expand ['Aa'] to ['az','Aa']