refactored message to decoder to be an abstract class, this allows end users to define their own message encodings
adding default props
Merge branch 'master' of github.com:linkedin/camus into linkedin-master

Conflicts:
	src/main/java/com/linkedin/batch/etl/kafka/coders/KafkaAvroMessageEncoder.java
My latest pom for the current dependency-light camus.
My latest KafkaMessageDecoder implementation, which should return the correct part of the Kafka messages, with an avro jsonDecoder.
Commented out the count stuff, since I'm not sure how to implement a proper KafkaMessageEncoder...