XML Nodes

Xml nodes are used during parsing to map sax events and elements to binding metadata for models and their fields.

ElementNode	XmlNode for complex elements.
WildcardNode	XmlNode for extensible elements that can hold any attribute and content.
UnionNode	XmlNode for union fields with at least one data class.
PrimitiveNode	XmlNode for text elements with simple type values.
StandardNode	XmlNode for elements with a standard xsi:type.
WrapperNode	XmlNode for wrapper class fields.