code: function createChildren(el, attr) {
  	var children = [];
  	for (var i = 0; i < el.childNodes.length; i++) {
  		children.push(createNode(el.childNodes[i], attr));
  	};
  
  	return children;
  }
docs: Recursively create vdom
  
  @param   Object  el    Parent element
  @param   String  attr  Attribute name that contains vdom key
  @return  Array         Child vnode or vtext