Update to use the latest HellaRedis

This updates HellaRedis and how it is used. The latest HellaRedis
takes a hash directly so this allows removing the
`RedisConnection`. This also changes the testing to use the
`ConnectionSpy` provided by HellaRedis. This allows testing that
the configuration was properly used when building a redis
connection.
Merge pull request #39 from redding/jcr-new-hella-redis

Update to use the latest HellaRedis