Forked repo, changes made to force this camel kafka component to produce and consume Strings. Originally, java serialization
was used to convert pojos received/sent through camel into bytes for kafka. Now we toString() and getBytes().

- Extracted the serializer implementation and made it pluggable within the Klistener (used by KafkaConsumer).
- Added new class, StringSerializer, implemented Kafka decoder/encoder interfaces.
- Removed the logback.xml configuration file, using only log4j for runtime logging configuration.
- Removed static library kafka-0.7.2, modified project pom to reference kafka core via remote repo.
- Bug fix, settings camel endpoint option 'producerType' to 'async' causes null pointer exception in kafka.