INTEXT-77 Add Kafka topic filter support for producer + consumer

* Add tests
* Add samples
* Update readme

Jira: https://jira.springsource.org/browse/INTEXT-77
Merge pull request #58 from relango/merge-master-kafka-topic-filter

* relango-merge-master-kafka-topic-filter:
  INTEXT-77 Add Kafka topic filter support for producer + consumer