This release includes critical bugfixes -- upgrade strongly recommended

Consumers

• Improve KafkaConsumer Heartbeat handling (dpkp PR 583)
• Fix KafkaConsumer.position bug (stefanth PR 578)
• Raise TypeError when partition is not a TopicPartition (dpkp PR 587)
• KafkaConsumer.poll should sleep to prevent tight-loops (dpkp PR 597)

Producers

• Fix producer threading bug that can crash sender (dpkp PR 590)
• Fix bug in producer buffer pool reallocation (dpkp PR 585)
• Remove spurious warnings when closing sync SimpleProducer (twm PR 567)
• Fix FutureProduceResult.await() on python2.6 (dpkp)
• Add optional timeout parameter to KafkaProducer.flush() (dpkp)
• KafkaProducer Optimizations (zackdever PR 598)

Clients

• Improve error handling in SimpleClient.load_metadata_for_topics (dpkp)
• Improve handling of KafkaClient.least_loaded_node failure (dpkp PR 588)

Documentation

• Fix KafkaError import error in docs (shichao-an PR 564)
• Fix serializer / deserializer examples (scribu PR 573)

Internals

• Update to Kafka 0.9.0.1 for integration testing
• Fix ifr.future.failure in conn.py (mortenlj PR 566)
• Improve Zookeeper / Kafka Fixture management (dpkp)