Updated docu:fixed screenshot links
Updated docu:fixed screenshot links

kensipe/logstash,kensipe/logstash,mesosphere/logstash,frankscholten/logstash,mesosphere/logstash,mesos/logstash,mesos/logstash,suppandi/logstash,alex-glv/logstash,suppandi/logstash,frankscholten/logstash,kensipe/logstash,frankscholten/logstash,kensipe/logstash,suppandi/logstash,mesosphere/logstash,alex-glv/logstash,frankscholten/logstash,suppandi/logstash,alex-glv/logstash,mesosphere/logstash,alex-glv/logstash