DOMNode = function DOMNode(agent, payload) {
        this.agent = agent;
        this.children = [];
        this.attributes = {};

        // set the payload
        if (typeof payload === "string") {
            payload = DOMHelpers.extractPayload(payload);
        }
        if (payload) {
            this.setPayload(payload);
        }
        this.agent.addNode(this);
    }
Constructor
@param {DOMAgent} the agent is passed to avoid circular relationships
@param {DOM.Node} node payload