Applies the supplied values to the template and overwrites the content of el with the new node(s).

@param {String/HTMLElement/Ext.Element} el The context element
@param {Object/Array} values The template values. See {@link #applyTemplate} for details.
@param {Boolean} returnElement (optional) true to return a Ext.Element.
@return {HTMLElement/Ext.Element} The new node or Element
function(el, values, returnElement) {
        var newNode = Ext.DomHelper.overwrite(Ext.getDom(el), this.apply(values));
        return returnElement ? Ext.get(newNode) : newNode;
    }