code: function (a, override) {
              var b = a.slice();
              if (override) {
                  b.reverse();
              }
              var i = 0, n, item;
              while (i < b.length) {
                  item = b[i];
                  while ((n = util.lastIndexOf(item, b)) !== i) {
                      b.splice(n, 1);
                  }
                  i += 1;
              }
              if (override) {
                  b.reverse();
              }
              return b;
          }
docs: Returns a copy of the array with the duplicate entries removed
  @param a {Array} the array to find the subset of unique for
  @param [override] {Boolean} if override is TRUE, util.unique([a, b, a]) => [b, a].
  if override is FALSE, util.unique([a, b, a]) => [a, b]
  @return {Array} a copy of the array with duplicate entries removed
  @member KISSY