Release v1.3.0.0

• Update to elasticsearch version 1.3.0 http://www.elasticsearch.org/downloads/1-3-0/
• Add setQuery() method to Elastica\Query\ConstantScore #653
• Be able to configure ES host/port via ENV var in test env #652
• Fix FunstionScore Query random_score without seed bug. #647
• Add setPostFilter method to Elastica\Query (http://www.elasticsearch.org/guide/en/elasticsearch/guide/current/_filtering_queries_and_aggregations.html#_post_filter) #645
• Add Reverse Nested aggregation (http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-aggregations-bucket-reverse-nested-aggregation.html). #642