DrBotIRC: remove XML-RPC echo

the server idea seems to work, let's have Echo implement this as a
test/example

DrBotIRC.py

@@ -49,19 +49,6 @@ class DrBotzoMethods:
 
         self.irc = irc
 
-    def echo(self, message):
-        """Just reply to the client, for testing purposes.
-
-        Args:
-            message     the message to echo
-
-        Returns:
-            message, unmodified.
-
-        """
-
-        return message
-
     def say(self, target, message):
         """Say a message in a channel/to a nick.