RabbitMQ Workers -- DelayedJob 'deploy' extraction

Removed all worker recipes from 'deploy'.  Added sneakers workers for handling sneakers/AMQP based workers.  Limited options currently.

Workers can be placed in the deploy structure:
```JSON
{
  "deploy": {
    "application": {
      "workers": {
        "delayed_job": [
          "queue1,queue2", "queue3"
        ],
        "sneakers": [
          "Workers::TestWorker", "Workers::MailerWorker"
        ]
      }
    }
  }
}
```

Sneakers wants an `$AMQP_URL` environment variable for the RabbitMQ server.  The VHOST is currently always `$RAILS_ENV`.  `$AMQP_EXCHANGE` can be overriden.  Default value is: `amqp.<application_shortname>`.