handler: if no default node, throw exception on unknown node
xmlnode: replace root and default node definition by a type enum
handler: replace StringBuffer by StringBuilder
xmlnode: name defaults to the class name
xmlparser: throw exception if root or default with parent
documentation: update package example
reflect: throw exception if instantiation fails
handler: use a separate stringbuilder for each node in the stack

This allows for nodes with children as well as content.
handler: remove useless else
xmlnode: add updateContent and resetContent

This will allow to handle child nodes inside the parent's content.
doc