Break DynamicSpout, KafkaConsumer, and SidelineSpout into separate modules

[Crim]

To provide clear separation of concerns between the DynamicSpout framework, the 'Sideline Spout' implementation, and the 'Kafka' consumer implementation, we should separate these out into maven modules.

[stanlemon]

@Crim I feel like the 0.9 milestone is a bit ambition, can we focus on production-readiness in 0.9 and concentrate more splitting in 0.10?

[Crim]

I think after #65 the only remaining blocker for this is SpoutConfig contains a reference to Kafka Consumer to set the default consumer class. That would need to be removed.