XML_Marshaller : Instances are now correctly unmarshalled. Also added changelog and cleaned setup.py.

   found while unmarshalling)

http://www.python.org/dev/peps/pep-0386/ it was wrong.
Update the version with an incremented extraversion number.

* use expatreader to parse xml trees for better performances 

Major part of code come from no longer maintained pyxml library.
Fully compatible with PyXML implementation, enable namespace support for
XML Input/Output.