Schema update + Post-build action + RabbitMQ Support

* Use JedisPool to fix concurrency issue with multiple running jobs
* Update Logstash event schema (https://logstash.jira.com/browse/LOGSTASH-675)
* Add more build data to the payload (build parameters, Jenkins ID, etc.)
* Move connection info into a global config shared between all jobs
* Add a post-build action to send multiple log lines as a single event
* Add support for RabbitMQ
* Bumped major version number to reflect changes