Newrelic

Started on adding support for redis in newrelic recipe (already supported in meetme plugin), but found some other things that could be improved. Changes:
- Adding new code block for meetme redis config, tied to the included redisio::enable recipe
- Changed meetme config for the rabbitmq block from symbol to string syntax
- Changed node['recipes'] to node.recipe?
- Added an if statement around the uwsgi meetme block unless stackname is pythonstack
- Had some issues with the use of stackname is various places (which is a side-effect of the current de-dupe effort) so had to clean up some of the references to have a successful converge

Since we don't really test newrelic, I used the following in .kitchen.local.yml:

```yaml
---
provisioner:
  attributes:
    newrelic:
      license: "my_personal_account_licence"
    stack_commons:
      stackname: 'pythonstack'
    pythonstack:
      demo:
        enabled: false
      webserver: 'nginx'
      nginx:
        sites:
          kitchensite:
            uwsgi_port: 666
suites:
  - name: sia
    run_list:
      - recipe[stack_commons::memcached]
      - recipe[stack_commons::rabbitmq]
      - recipe[nginx]
      - recipe[stack_commons::redis_single]
      - recipe[stack_commons::newrelic]
```
Actually I'm still working on this branch to add mysql support, I've noticed redisio was left over so it would be removed in another PR :wink: 
good spot :+1: