Add support for RabbitMQ username and password for ircwrite

I`ve got a RabbitMQ Server with username and password.
Without this changes in this PR i got an error after "Read empty data, calling disconnect".

```
013-10-02 20:16:10,344 - INFO - Starting IRCProcess Read
2013-10-02 20:16:10,355 - INFO - Starting IRCProcess Write
2013-10-02 20:16:10,359 - DEBUG - <IRCProcess(irc_read, started daemon)> started on 5754
2013-10-02 20:16:10,361 - DEBUG - <IRCProcess(irc_write, started daemon)> started on 5755
2013-10-02 20:16:12,047 - DEBUG - :andybenderbot!~andybende@dslb-084-062-142-016.pools.arcor-ip.net JOIN #andyandy
2013-10-02 20:16:12,047 - DEBUG - Adding Message to RabbitMQ: :andybenderbot!~andybende@dslb-084-062-142-016.pools.arcor-ip.net JOIN #andyandy
2013-10-02 20:16:12,120 - DEBUG - :cameron.freenode.net 353 andybenderbot @ #andyandy :andybenderbot @Sermer
2013-10-02 20:16:12,120 - DEBUG - Adding Message to RabbitMQ: :cameron.freenode.net 353 andybenderbot @ #andyandy :andybenderbot @Sermer
2013-10-02 20:16:12,172 - DEBUG - :cameron.freenode.net 366 andybenderbot #andyandy :End of /NAMES list.
2013-10-02 20:16:12,172 - DEBUG - Adding Message to RabbitMQ: :cameron.freenode.net 366 andybenderbot #andyandy :End of /NAMES list.
2013-10-02 20:16:13,370 - ERROR - Read empty data, calling disconnect
2013-10-02 20:16:13,371 - ERROR - Socket closed while authenticating indicating a probable authentication error
Process irc_write:
Traceback (most recent call last):
  File "/usr/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/usr/lib/python2.7/multiprocessing/process.py", line 114, in run
    self._target(*self._args, **self._kwargs)
  File "/home/vagrant/BenderEnv/local/lib/python2.7/site-packages/BenderBot-1.0.0b-py2.7.egg/BenderBot/IRCProcess.py", line 51, in irc_write
    queue.subscribe()
  File "/home/vagrant/BenderEnv/local/lib/python2.7/site-packages/BenderBot-1.0.0b-py2.7.egg/BenderBot/BenderMQ.py", line 51, in subscribe
    self.__connect()
  File "/home/vagrant/BenderEnv/local/lib/python2.7/site-packages/BenderBot-1.0.0b-py2.7.egg/BenderBot/BenderMQ.py", line 24, in __connect
    raise Exception('Unable to connect to %s: %s' % (self.host, e))
Exception: Unable to connect to localhost: 
2013-10-02 20:16:14,363 - ERROR - IRC Write process alive: False
2013-10-02 20:16:14,364 - WARNING - Shutting down IRC Read process
2013-10-02 20:16:14,364 - ERROR - BenderBot shutting down
2013-10-02 20:16:14,365 - WARNING - Waiting 60 seconds before restarting...
2013-10-02 20:17:14,427 - INFO - connecting to irc.freenode.net:6667
2013-10-02 20:17:14,669 - INFO - setting nick to andybenderbot
```