function SimpleNode(properties) {
        $.extend(this, properties);
    }
A SimpleNode represents one node in a SimpleDOM tree. Each node can have
any set of properties on it, though there are a couple of assumptions made.
Elements will have `children` and `attributes` properties. Text nodes will have a `content`
property. All Elements will have a `tagID` and text nodes *can* have one.

@constructor

@param {Object} properties the properties provided will be set on the new object.