Merge r1140 from py3k: add support for python 3 to core genshi components (genshi.core, genshi.input and genshi.output): * default input and output encodings changed from UTF-8 to None (i.e. unicode strings) * Namespace and QName objects do not call stringrepr in __repr__ in Python 3 since repr() returns a unicode string there. * track changes to expat parser in Python 3 (mostly it accepts bytes instead of strings)

--- a/genshi/output.py
+++ b/genshi/output.py
@@ -27,7 +27,7 @@
 __docformat__ = 'restructuredtext en'
 
 
-def encode(iterator, method='xml', encoding='utf-8', out=None):
+def encode(iterator, method='xml', encoding=None, out=None):
     """Encode serializer output into a string.
     
     :param iterator: the iterator returned from serializing a stream (basically