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.

Fixed compile error in ScanCursor with Java 6.

Orignal pull request: #76.