Fix the unit tests by adding dispatch tables for DateTime and Binary.
I'm not convinced this is the right thing to do...  InstanceType makes no sense any longer.
diff --git a/Lib/xmlrpclib.py b/Lib/xmlrpclib.py
index 6fb6c68..bac0a9f 100644
--- a/Lib/xmlrpclib.py
+++ b/Lib/xmlrpclib.py
@@ -749,6 +749,8 @@
             # store instance attributes as a struct (really?)
             self.dump_struct(value.__dict__, write)
     dispatch[InstanceType] = dump_instance
+    dispatch[DateTime] = dump_instance
+    dispatch[Binary] = dump_instance
 
 ##
 # XML-RPC unmarshaller.