Update Genshi to 0.7.

Version 0.7
http://svn.edgewall.org/repos/genshi/tags/0.7.0/
(Jan 27 2013, from branches/stable/0.7.x)

* Add support for Python 3.1, 3.2 and 3.3 (via 2to3) and for PyPy. The
  majority of the coding was done in a sprint run by the Cape Town Python
  Users Group with financial assistance from the Python Software Foundation.
* Default input and output encodings changed from UTF-8 to None (i.e. unicode
  strings).
* Skip Mako benchmarks if Mako isn't installed (rather than failing
  completely).

(obache)