code: function clone(obj1, obj2, index) {
    index = index || 0;
    for (var i in obj2) {
      if ('object' == typeof i) obj1[i] = recursiveMerge(obj1[i], obj2[i], index++);
      else obj1[i] = obj2[i];
    }
    return obj1;
  }
docs: Merge the properties from one object to another object. If duplicate keys
  exist on the same level, obj2 takes presedence over obj1.
  
  @param {Object} obj1
  @param {Object} obj2
  @param {Number} index
  @return {Object}
  @api private