Streamsx-kafka

This version of the toolkit includes fixes for issues 46 & 48.

This version of the toolkit includes:

* Optional input port added to the **KafkaConsumer** operator to allow for dynamically adding and remove topics partitions. When adding a topic partition, the start offset can be specified to allow applications to begin consuming from specific offsets (rather than only the beginning or end of a topic-partition). The [KafkaConsumerInputPortSample](https://github.com/IBMStreams/streamsx.kafka/tree/develop/samples/KafkaConsumerInputPortSample) demonstrates how to use this functionality.
* The **KafkaConsumer** operator can now output the offset, partition and timestamp for each message it consumes. This functionality adds the following new parameters:
* outputOffsetAttributeName
* outputPartitionAttributeName
* outputTimestampAttributeName
* The **KafkaConsumer** operator's **startPosition** parameter now includes a `Time` option. This option, when used in conjunction with the new **startTime** parameter, allows for specifying the timestamp that the consumer should begin consuming from.
* The **KafkaProducer** operator now provides the ability to specify the timestamp value to add to the records being written to the topics. This is supported via the new **timestampAttribute** parameter.

This release also fixes a number of bugs, including a critical memory issue - 42

This is a minor release that includes the fix for 34.

This version of the Kafka Toolkit includes the following:

* The **KafkaConsumer** operator now includes a `clientId` parameter that allows for programatically setting Kafka's `client.id` configuration property. This parameter is useful when implementing load balancing using Streams' UDP feature. Take a look at the [KafkaClientIdSample](https://github.com/IBMStreams/streamsx.kafka/tree/v1.1.0/samples/KafkaClientIdSample) for an example of how to use this parameter.
* Bug fixes ([Issues](https://github.com/IBMStreams/streamsx.kafka/issues?q=is%3Aissue+is%3Aclosed+label%3A%22Target%3A+v1.1.0%22) fixed in this release)

This is the first release of the Kafka Toolkit. It contains operators to both consume from and produce to Kafka topics. This version of the toolkit supports **Apache Kafka v0.10.x**.

The toolkit contains the following features:
* At least message delivery semantics
* Support for dynamic and static topics when writing messages to Kafka topics
* Specify Kafka properties via a properties file or application configuration
* Begin consuming from either the beginning or the end of a topic
* Support for user-defined partitioners and serializers/deserializers
* Automatic determination of serializer/deserializer for keys and messages
* Support for non-string keys and messages