ruflin/Elastica — pull request #725 by audriusb (2014-11-19 10:06:55+00:00)
Title: Introduced Bool filter cache and cache key parameters support

According to documentation (http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-bool-filter.html#_caching_2) bool filter dies support _cache and _cache_key, but it was completely ignored on Elastica\Filter\Bool