Added quorum_lookup

quorum_lookup picks lookup_result_enties by following rules:
1. If there are quorum lookup_result_enties with the same
timestamp, they are the final result
2. Otherwise the final result is lookup_result_enties with
the greatest timestamp
... because commonly known lookup operation is synchronous and goes one-by-one into specified groups until it finds out correct object. Parallel lookup is intended to check ALL specified groups in parallel and return all related information.