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
* Most web.xml servlet API versions updated to 3.0 for ASYNC support
* httpsession-xml is left at 2.5 to ensure compatability & remove ASYNC
* Remove @Override on interface override
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
