Favor lettuce because of multiplexing and improved scalability.
Using lettuce requires a fixed number of connections hence using
lettuce improves application scalability.
Fixes gh-652
This prevents the embedded redis from being picked up in ComponentScan
in any of the samples unless the @EnableEmebeddedRedis annotation is used.
Polish gh-184
Previously there was a possibility that Session to WebSocket mapping was
leaked if keyspace notifications were not enabled in Redis.
To resolve this the RedisHttpSessionConfiguration now ensures that Redis
is configured to enable Keyspace notifications.
Fixes gh-76 gh-81
