Upgrade to JRedis master

DATAREDIS-54, DATAREDIS-174, DATAREDIS-129

- Switch to original JRedis for 2.6 support

- Remove base64 encoding as new JRedis supports binary
keys

- Add JredisPool interface to replace removed
JRedisService and pool implementation

- Temporarily switch integration tests to use
non-pooled connections

- Throw more specific Exception on JRedis connection
failures
Add default implementation of JredisPool

- Add DefaultJredisPool to pool JRedis connections

- Prevent returning the same resource to the pool
multiple times on JredisConnection close

- Fixes DATAREDIS-154 previous JRedis pool left
broken connections in the pool