Issue #1148 Add KafkaOutput
Allow restart attempts on failure.
Issue #1148 Add KafkaInput
Log brokerProducer errors in KafkaOutput
Fix the encoder check to not Queue a nil message
Add a stat to track discarded messages, encode() with no output or error
keeping the errChan empty more important than new packs

if heka is busy, inchan wins over errChan and QueueMessage will block
forever
Merge pull request #1169 from imgix/kafka_output

keeping the errChan empty more important than new packs
Improve producer errChan handling and prevent QueueMessage deadlocks
Add a goroutine to offload the Kafka errChan processing and prevent deadlocks
Incorporate review feedback
Merge pull request #1174 from mozilla-services/kafka_output

Add Kafka Input and Output plugins