deserialize method
Deserializes the FML template elements, attributes and children
Implementation
@override
void deserialize(XmlElement xml) {
// deserialize
super.deserialize(xml);
// properties
allow = Xml.get(node: xml, tag: 'allow');
onstart = Xml.get(node: xml, tag: 'onstart');
ondismissed = Xml.get(node: xml, tag: 'ondismissed');
}