Update ElasticaQuerySubscribers to use SearchableInterface and Query

Fixing issue as mentioned in #109 - ElasticaQuerySubscribers now use the `Elastica\SearchableInterface` and `Elastica\Query` classes, instead of the old `Elastica_Searchable` and `Elastica_Query` in the `if` of the subscriber itself. 

Also, simply added a check to see if the result set has Aggregation - in addition to `hasFacets` I added `hasAggregations` and if true, simply add the aggregations on as a special parameter.