fixup the script and rebuid the API cleanup provided accessors for a lot

fixup the script and rebuid the API cleanup provided accessors for a lot

* doc/libxslt-api.xml doc/libxslt-decl.txt doc/libxslt-refs.xml
  doc/parsedecl.py: fixup the script and rebuid the API
* libxslt/extensions.h: cleanup
* python/generator.py python/libxslt-python-api.xml python/libxslt.c
  python/libxsltclass.txt: provided accessors for a lot of the
  tructures involved in the transformation. Stylesheet and
  transformation python object don't free automatically the
  encapsulated object when deallocated.
* python/tests/Makefile.am python/tests/basic.py
  python/tests/extfunc.py python/tests/pyxsltproc.py:
  updated the examples
Daniel