Terms filter lookup should accept routing and cache params

[MrHash]

As described here: http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-terms-filter.html#_terms_lookup_mechanism

Should the argument list be extended after $index?
https://github.com/ruflin/Elastica/blob/master/lib/Elastica/Filter/Terms.php#L73

[ruflin]

It looks like the first 4 are mandatory, the additional ones are optional one. So instead of extending, I would suggest to replace $index with $options = array(). And to make it BW compatible, in case it isn't an array, $index is picked. Like this also params can be added in the future without having to change the function.