Test usage of empty stdClass.

In method FunctionScoreQueryTest::addRandomFunction.

Add parameters to nested query.

Add FunctionScoreQuery::addFieldValueFactorFunction test.

Add field argument to aggregation constructor.

Fix FuzzyLikeThisQuery to return correct format.

Use empty stdClass instead of empty array.

Make modifier argument optional.

In method addRandomFunction.
Elasticsearch expects object not array and empty array will not be made into object.

In method addFieldValueFactorFunction.
Elasticsearch documentation says that it is optional.

Merge branch 'remove-references-to-suggester' of https://github.com/bcremer/ElasticsearchDSL into bcremer-remove-references-to-suggester

# Conflicts:
#	src/Search.php

Fix query endpoint dependency

Fix missing dependencies for Search class

Suggester namespace was removed in commit
832934df.