libxslt

* libxslt/extensions.c libxslt/transform.c: fixing bug #101602
  for extension modules init and shutdown callbacks, check that
  they are now called when needed.
* python/libxsl.py python/libxslt-python-api.xml python/libxslt.c:
  started adding the extension module support at the Python level.
  Still a strange bug to hunt down left.
Daniel