Adds consumer hookish ways to Publish Task events to redis and other Pub...

...Sub modules. Tests included

Lemme know what you think. 
The code needs to be reorganized I think (as far as what modules live where). Also its kinda weird to me that I'm calling them "PubSub" I mean there is no Sub just Pub. 

The Django settings end up looking like this
```
import logging

HUEY = {
            'backend': 'huey.backends.redis_backend',  # required.
            'name': 'unique name',
            'connection': {'host': 'localhost', 'port': 6379},
            'consumer_options': {'workers': 4,
                                 'publisher': 'huey.consumers.pubsub.RedisPubSub',
                                 'pubsub_options': {'host': 'localhost', 'port': 6379, 'channel':'mychannel'},
                                 'loglevel': logging.DEBUG
            },
}
```

I suppose if you went this route you could also include a DjangoORM Publisher pretty easily.