wxPython Merge #2 of 2.4 branch --> HEAD (branch tag: wxPy_2_4_merge_2)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@21593 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/src/image.i

@@ -333,6 +333,8 @@ public:
             return bitmap;
         }
     }
+
+    %pragma(python) addtoclass = "def __nonzero__(self): return self.Ok()"
 };