Upgraded the Jedis client to v2.4.2 for compilation, as the shiro-redis
modules causes runtime exceptions if used with components having
external dependencies to libs using a more recent version of Jedis.
Added support for explicit declaration of Redis key prefixes for both
session and cache keys.
Added JUnit test
Merge pull request #1 from theChefArchitect/master

Jedis upgrade & custom Redis key prefixes