merging current boost/python and libs/python from trunk into release branch

[SVN r71226]

example/README

@@ -14,4 +14,3 @@ http://www.boost.org/more/getting_started.html for details about the
 If you move this example from its place in the Boost development tree
 you'll need to edit the two lines indicated in Jamroot and
 boost-build.jam.
-

src/converter/builtin_converters.cpp

@@ -431,7 +431,10 @@ namespace
           if (!result.empty())
           {
               int err = PyUnicode_AsWideChar(
-                  (PyUnicodeObject *)intermediate
+#if PY_VERSION_HEX < 0x03020000
+                  (PyUnicodeObject *)
+#endif
+                    intermediate
                 , &result[0]
                 , result.size());