CouchDB River: Support couchdb filter query parameters

[mahendra]

Couchdb filters support query parameters. It will be good to support this in the Elasticsearch couchdb river plugin.

Details of the couchdb filters are documented at
http://blog.couchone.com/post/468392274/whats-new-in-apache-couchdb-0-11-part-three-new.

The parameters can be provider under:

{
    "couchdb" : {
        "filter" : "test",
        "filter_params" : {
            "param1" : "value1",
            "param2" : "value2"
        }
    }
}

[kimchy]

CouchDB River: Support couchdb filter query parameters, closed by 735ad0d.