code: function unique (a) {
                      if(!(a instanceof Array)) return a;
  
                      var visited = [],
                          unique  = [];
  
                      libs.object.each(a, function (item) {
                          if(visited.indexOf(item) === -1) {
                              unique.push(item);
                              visited.push(item);
                          }
                      });
                      return unique;
                  }
docs: Gets an array of unique items from the current array.
  @param {Array} a The Array object to operate on.
  @returns {Array} A new array with no duplicate values.
  @function