SAMZA-270; fix erasure warning in TestKeyValuePerformance
SAMZA-224. Fix race condition in TestStatefulTask
SAMZA-275: Fix logging of exception stack traces at debug level.
SAMZA-249; skip git add in generate-javadocs.sh
Merge branch 'master' into zmerge

Conflicts:
	samza-kafka/src/main/scala/org/apache/samza/checkpoint/kafka/KafkaCheckpointManager.scala
SAMZA-7: Rewrite Container section of docs to bring it up-to-date. Reviewed by Jakob Homan.
Merge branch 'master' into s71