Added new callback methods:
 + .onMessageReceived()
 + .sendMessage()

Connection handling refactored from demo example to something more useful.
All .atSomething() callback renamed to .onSomething().

Added better .onExit() message.
Added docstrings.

To:
 .__init__()
 .onMessageReceived()
 .sendMessage()
 .onExit()
Added two more configuration variables:

 RABBITMQ_ALEPH_VIRTUALHOST
 RABBITMQ_ALEPH_INPUT_QUEUE
 RABBITMQ_ALEPH_OUTPUT_QUEUE
 RABBITMQ_ALEPH_INPUT_KEY
 RABBITMQ_ALEPH_OUTPUT_KEY

So far, they are just for test purposes.