allow to specify child elements of Lists, Sets or transient elements by
their IXmlObjectBuilder.
Bug fix. CurrentClass was lost when elements have been ignored (because
no XmlElementDescriptor exists for them).
revisit method definitions and names
add method to go to the next element of a specific type, without leaving
the current sub-tree based at the given path
match elements on closing tag instead of opening tag in pull
add initial serializer framework
use null for the empty namespace
Add reflection based serializer.
update package structure and class names
refactor serialization, unify builders and serializers
add builder for Maps of ElementDescriptors
version 0.2