DATAREDIS-304 - Add support for SSCAN command.

SSCAN command is natively supported by jedis and can be emulated for lettuce.
JRedis and SRP will throw UnsupportedOperationException.

sScan is available on RedisConneciton and RedisSetOperations returning basically a Cursor that allows iteration over the defined values for a given key.

Currently the jedis driver does not directly expose the binary version of sscan which leads to invalid results when using a non String compatible converter along with the RedisTemplate. We’ll change this as soon as a newer version of jedis is available.

Along the way loading behavior of ScanCursor has been fixed, preventing it from indicating next values available when there effectively are no more.

Orignal pull request: #76.
DATAREDIS-309 - Refactor test profiles to support more than 2 versions.

We’ve added a customized SpringJUnit4Runner and TestRule that allow us to use a more relaxed strategy when dealing with @IfProfileValue. Basically we have added ‘+’ as sort of wildcard indicating tests should be executed for version X and all its successor.

This allows us to run test valid starting 2.6 for 2.8 as well, while those only valid for 2.8 are not executed against eg. redis 2.6.17.

Orignal pull request: #76.