Gathering Docker log files with fluentd, sending to Elasticsearch, viewing with Kibana

This pull request includes changes to the Salt setup to add a fluentd instance to each node. This fluentd instance will try to send the logs it has gather from the local Dockerfiles to port 9200 of the enclosing machine (e.g. a GCE VM). 

The contrib/loggimng directory has an example scenario that contains a simple web server (pod specification, service specification), Elasticsearch (pod and service specification) and Kibana (pod and service specification). It also contains the Dockerfile used for the fluentd manifest that is deployed by salt.