Add support for Kibana 4

This changeset adds support for Kibana 4. Kibana 4 is very different from Kibana 3.x in that it is a JVM based application. Previous versions of Kibana were standalone JavaScript applications that only interacted with ElasticSearch as a backend.

In addition, the example in this role was updated to use a standalone ElasticSearch instance vs. the embedded ElasticSearch in Logstash.
Tracked this down to an option for the Rack ReverseProxy class within Kibana. `true` is what we want here, despite the bad comment.