Modifications to Spout code to allow for metric registration

Fixes: #445
getSpout(transform, metrics) is called from getSpout and passed the metricFactory. metricFactory is appended to in registerMetrics call, so all metrics should show up in that def. Are you talking about KafkaSpout and KestrelSpout here? There yes, we don't do anything with metrics, but now that RichStormSpout is in tormenta we can use that class instead and register the metrics. Internally we create our own KafkaSpout and pass the metrics to RichStormSpout to be registered