Add a "chain" method which chains multiple Consumers into a single Consumer.
Added a general-use BatchConsumer that has start() and end() methods which can be used by various components that support batching to notify this type of Consumer that a batch has started and ended. Since it is an extension of Consumer, the accept method will be called for each item in a batch, just as it would in a single-use case.
Updated Processor API to make it efficient by baking in the event Consumer passed into the constructor and tweaking the implementation of batch. Also added support for the BatchConsumer when processing batches.
Updated gradle wrapper to 1.7-rc-2, bumped Netty version to 4.0.6