add ByteStringSerializer#contramap
add ByteStringDeserializer#map
update scala 2.11.2 and akka 2.3.5

akka 2.3.2 and scala 2.11.0 are so terrible!

http://akka.io/news/2014/05/22/akka-2.3.3-released.html

> If you were using Akka 2.3.2 for Scala 2.11.0 you need to update immediately, because serialization was broken in Scala
should not send message when channels empty
add RedisSubscriberActor#onErrorReply
Merge pull request #52 from xuwei-k/no-send-message-when-empty

should not send message when channels empty
Merge pull request #53 from xuwei-k/onErrorReply

add RedisSubscriberActor#onErrorReply
Merge pull request #47 from xuwei-k/map-contramap

add ByteStringSerializer#contramap, ByteStringDeserializer#map
Merge pull request #49 from xuwei-k/update-akka-and-scala

update scala 2.11.2 and akka 2.3.5
use ActorRefFactory instead of ActorSystem
Merge pull request #55 from xuwei-k/actor-ref-factory

use ActorRefFactory instead of ActorSystem
1.4.0
Update readme ( add bintray Latest Version Download Badge)
fix test: already used key in ScriptingSpec
README : Update coverage badge
update dependencies/plugin
Update readme: change version to 1.4