Function extend

src/flow.js:1583–1592

* Extends the destination object `dst` by copying all of the properties from * the `src` object(s) to `dst`. You can specify multiple `src` objects. * @function * @param {Object} dst Destination object. * @param {...Object} src Source object(s). * @returns {Object} Reference to `dst`.

(dst, src)

   * @returns {Object} Reference to `dst`.
   */
  function extend(dst, src) {
    each(arguments, function(obj) {
      if (obj !== dst) {
        each(obj, function(value, key){
          dst[key] = value;
        });
      }
    });
    return dst;
  }
  Flow.extend = extend;

  /**