Support bytes

[elbaro]

def hashi(self, key, replica=0):
        """Returns a ketama compatible hash from the given key."""
        dh = self._listbytes(md5(str(key).encode("utf-8")).digest())
        ...

hashi(b'abc') returns in dh=md5(b"b'abc'") instead of dh=md5(b'abc').