add support for python 3 to remaining genshi.template components: * minor changes to track encoding=None API change in core genshi modules. * genshi/template/directives: * slightly odd syntax changes to make the 2to3 .next() fixer pick up *stream.next() * minor test fix for change in behaviour of division (/) in Python 3. * genshi/template/loader: * add 'b' to file modes to ensure it's loaded as bytes in Python 3. * use not isinstance(s, unicode) instead of isinstance(s, str) since the former is correctly converted by 2to3.

--- a/genshi/template/tests/directives.py
+++ b/genshi/template/tests/directives.py
@@ -1137,8 +1137,8 @@
           <py:with vars="x = x * 2; y = x / 2;">${x} ${y}</py:with>
         </div>""")
         self.assertEqual("""<div>
-          84 42
-        </div>""", tmpl.generate(x=42).render(encoding=None))
+          84 %s
+        </div>""" % (84 / 2), tmpl.generate(x=42).render(encoding=None))
 
     def test_semicolon_escape(self):
         tmpl = MarkupTemplate("""<div xmlns:py="http://genshi.edgewall.org/">