Merging develop to master for new release

Fix readthedocs domain

Update coveralls settings

Actually use ClientInterface

corrects php docblock in result-of-a-select-query

fix typo on docs index.md

It's a pretty glaring error on the main page (and thus on Google results).

Stats percentiles

Chcek existance of stats value before returning.

Added option to add multiple boostqueries to dismax parser

Fixed some types.

added support for replicas in distributed search

Added unit tests for QueryType\Select\Query\Component\DisMax::addBoostQuery, addBoostQueries.

addition of the replicas property so the request builder can use both shards and replicas in the shard param

Allow symfony/class-loader 3.0 to be installed

stop allowing travis test failures for HHVM

Merging 3.5.1 fixes to develop branch

Fix BC break in 3.5.0 release