Markov: when learning lines, don't include the part direct addressing

e.g. if i say 'dr_botzo: hello dude', he only learns 'hello dude'.
this is mainly being done because the bot's name being in the brain
so many times was getting kind of silly, especially in channels that
have lots of conversations with the bot

modules/Markov.py

@@ -106,6 +106,8 @@ class Markov(Module):
         """Learn from IRC events."""
 
         what = ''.join(event.arguments()[0])
+        my_nick = connection.get_nickname()
+        what = re.sub('^' + my_nick + '[:,]\s+', '', what)
 
         # don't learn from commands
         if self.trainre.search(what) or self.learnre.search(what) or self.replyre.search(what):