code: function serial(list, callback, errback) {
      if (base.isArray(list)) {
          return callNext(list, [], false);
      } else {
          throw new Error("When calling comb.serial the first argument must be an array");
      }
  }
docs: Executes a list of items in a serial manner. If the list contains promises then each promise
  will be executed in a serial manner, if the list contains non async items then the next item in the list
  is called.
  
  @example
  
  var asyncAction = function(item, timeout){
  var ret = new comb.Promise();
  setTimeout(comb.hitchIgnore(ret, "callback", item), timeout);
  return ret.promise();
  };
  
  comb.serial([
  comb.partial(asyncAction, 1, 1000),
  comb.partial(asyncAction, 2, 900),
  comb.partial(asyncAction, 3, 800),
  comb.partial(asyncAction, 4, 700),
  comb.partial(asyncAction, 5, 600),
  comb.partial(asyncAction, 6, 500)
  ]).then(function(results){
  console.log(results); // [1,2,3,4,5,6];
  });
  
  
  
  @param list
  @param callback
  @param errback
  @static
  @memberOf comb