fix api_version.

support SCRAM.

fix: api_version not used while producing to kafka

support SASL auth & basic consumer.

latest release to support API version V0 (supported in kafka 0.8 or b…

…efore).

support ssl.

bugfix: avoiding too many pending timer errors by using ngx.timer.every

support kafka 0.10.

bumped version to 0.06.