Feature/logstash

adds "--logstashtype" and "--logstashurl" CLI options.

--logstashtype: logs generated will be sent to the logstash server with the provided type. Defaults to "" (disabled). Examples:

# The following results in logs that can be queried with the "serviced-master" type in elastic search/kibana:
serviced -master --logstashtype="serviced-master" 

# The following results in logs that can be queried with the "serviced-add-host-foo" type in elastic search/kibana:
serviced add-template foo --logstashtype="serviced-add-host-foo"

--logstashurl: defines the logstash url and port. Defaults to "172.17.42.1:5042".