added KafkaSink
added Byte and Long Sink
added KafkaAvroSink
added KafkaAvroSink
added documentation
switched Store to use kafka.producer.AyncProducer
added conjar repo to resolve  "com.twitter"%"kafka_2.9.2"%"0.7.0"
implemented multiPut
fixed broken build on 2.10
introduced AsyncSemaphore and FuturePool in KafkaStore.
introduced AsyncSemaphore and FuturePool in KafkaStore.
implemented close method
switched to bijections 0.6.0
added KafkaStoreSpec
added multiput spec
added KafkaSink convert spec
add filter spec
added avro specs
added pendingUntilFixed to prevent CI failure
made Sink and Store serializable