.commit() Listeners - storm-kafka

[Michael Schonfeld]

Hey guys,

I'd like to add event listeners to KafkaSpout's .commit(). Specifically,
I'm looking to add the ability to listen when a commit happens, and get the
last completed offset. It'll look somewhat like this:
```
new KafkaSpout(SpoutConfig).addCommitListener(KafkaCommitListener);

public interface KafkaCommitListener {
  void onCommit(PartitionManager manager, Long lastCompletedOffset);
}
```

Should I simply submit a PR? Or, as per storm-contrib's instructions, may I
get commit permissions to that repo?

Thanks,
- Michael S