Add Reverse Nested aggregation.
Merge pull request #642 from rayward/reverse-nested

Add Reverse Nested aggregation.
Fix '0' as valid request data

`Index->analyze('0', array('analyzer' => 'language_query_analyzer'))` would throw an `ElasticsearchIllegalArgumentException[text is missing]` because the request data is not passed.
Fix '0' for Guzzle Transport
Ignore empty array
Ignore empty array on guzzle
use different comparison
add test for post with 0 body
Merge pull request #640 from Tobion/patch-1

Fix '0' as valid request data
Add branch alias for 1.2
Merge pull request #644 from merk/patch-1

Add branch alias for 1.2
Add setPostFilter method to Elastica\Query
update changes.txt file
Merge pull request #645 from krzaczek/fix-query-post-filter

Add setPostFilter method to Elastica\Query
Add refresh to test to prevent it from failing randomly
Add refresh to test to prevent it from failing randomly
Fix FunstionScore Query random_score without seed bug
Merge pull request #647 from krzaczek/fix-random-score

Fix FunstionScore Query random_score without seed bug
[Test] Be able to configure ES host/port via ENV var in test env
Merge pull request #652 from lyrixx/test-env

 	[Test] Be able to configure ES host/port via ENV var in test env