Changes the way that command sets are duplicated in a merge to be sure class

attributes are propagated.

src/commands/cmdset.py

@@ -202,7 +202,7 @@ class CmdSet(object):
         Returns a new cmdset with the same settings as this one
         (no actual commands are copied over)
         """
-        cmdset = CmdSet()
+        cmdset = self.__class__()
         cmdset.__dict__.update(dict((key, val) for key, val in self.__dict__.items() if key in self.to_duplicate))
         cmdset.key_mergetypes = self.key_mergetypes.copy() #copy.deepcopy(self.key_mergetypes)
         return cmdset