- set default codec to json - remove use of @format
- set default codec to json
- remove use of @format

tinglinux/logstash-kafka,Aloomaio/logstash-kafka,Aloomaio/logstash-kafka,joekiller/logstash-kafka,opentable/logstash-kafka,tinglinux/logstash-kafka,opentable/logstash-kafka,joekiller/logstash-kafka