Improved docs : blocking cmds + pubsub

[thijsterlouw]

Hi, I thought it would be good to point out to your users that redis_client processes commands in a blocking way. The erl-redis library is very well written, so this blocking behavior was a bit surprising to me. According to your benchmarks it is still plenty fast, so for many users it will probably not matter. I also suggest more documentation for the pub/sub-usage (which some other redis libraries do not support).

[litaocheng]

this library was written in last year when the redis is in the version 1.2.6. I will make it work with redis 2.4.2.
It will support channel/pattern pub/sub, piplining. Thank you for your attention! :)