DATAREDIS-268 - Add support for 'CLIENT LIST'.

'RedisConnection' and 'RedisTemplate' have been extended by 'clientList' retrieving client informations from redis. 'RedisClientInfo' provides access via specified getters as well as an more general approach directly using the keys (like 'qubuf').

The operation is available for 'jedis', 'lettuce' and 'srp'.

Original Pull Request: #53