Log Message:
Update elasticsearch to 1.3.1.

bug fixes
- Internal: Support parsing Lucene minor version strings
- Aggregations:
  - The nested aggregator should also resolve and use the parentFilter
    of the closest reverse_nested aggregator.
  - Geo bounds aggregation outputs aggregation name
  - Make _source parsing in top_hits aggregation and search API consistent
  - Tracking scores should be applied properly for top_hits aggregation.