Just Pushed: Cluster Shard Allocation Awareness

Heya,

Just pushed support for "awareness" based allocation of shard and
replicas (i.e. rack aware allocation, or "zone" aware allocation). Explained
here in the issue:
https://github.com/elasticsearch/elasticsearch/issues/1352.

-shay.banon

Thanks for this. I will definitely test as we have a few racks of ES nodes.