INTEXT-44 - Add Kafka Support

* Add Inbound adapter
* Add Outbound adapter
* Add serialization
* Initial Documentation
* Add unit tests
* Add async producer
* Support Kafka 0.8
* Add Kafka Sample

See: https://jira.springsource.org/browse/INTEXT-44
INTEXT-44 - Polishing

* Upgrade to Gradle 1.6
* Upgrade Sonar plugin to SonarRunner
* Upgrade a few dependencies (e.g. JUnit, Spring Integration)
* Remove deprecations (e.g. JUnit)
* Convert spaces to tabs
* Add author tags
* Add @since
Merge pull request #42 from sobychacko/INTEXT-44

* sobychacko-INTEXT-44:
  INTEXT-44 - Polishing
  INTEXT-44 - Add Kafka Support
Moved Kafka Test Context Files
Updated list of available modules
Update README.md
INTEXT-81 Fixing bug in decoding message streams
* adding a null check on the key decoder

https://jira.springsource.org/browse/INTEXT-81
INTEXT-81 Add unit tests
Merge pull request #52 from bellwethr/master

* bellwethr-master:
  INTEXT-81 Add unit tests
  INTEXT-81 Fixing bug in decoding message streams * adding a null check on the key decoder
INTEXT-65 Add JGroups Extension
Merge pull request #43 from kcrimson/master

* kcrimson-master:
  INTEXT-65 Add JGroups Extension
INTEXT-83 Update to Kafka 0.8.0-beta1
Merge pull request #55 from ghillert/INTEXT-83

INTEXT-83 Update to Kafka 0.8.0-beta1
INTEXT-84 Kafka: Enhance Avro serialization support
Merge pull request #56 from sobychacko/INTEXT-84

* sobychacko-INTEXT-84:
  INTEXT-84 Kafka: Enhance Avro serialization support
INTEXT-89 Fix Inbound Stop When No Server

The reconnection task was not canceled in doStop().
INTEXT-90 Update Paho Client to 0.4.0

Add eclipse paho repo.
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
INTEXT-92 Kafka: Add support for specifying any producer/consumer property

* Update README.md for producer and consumer properties usage