Upgrade Akka to 2.3 using 2.2 IO pipeline (#65)

Akka IO Pipelines which Redisreact depends on in the network layer
are removed from Akka 2.3 [1]. Since Reactive Stream will take place
of pipelines in Akka 2.4, let's just borrow the old pipeline
implementation for Akka 2.3.

[1] https://groups.google.com/forum/#!topic/akka-user/8fZ75MlVEYc
Bump version to 0.5-SNAPSHOT
Add some ReconnectionSettings, with Constant and Exponential policies
Add support for reconnection if there is a policy for it
Add a simple test for reconnection
Organize imports
Merge pull request #69 from debasishg/wip/akka-2.3

Prepare 0.5-SNAPSHOT with Akka 2.3 support (#65)
Merge pull request #72 from fractaloop/issue-71-reconnections

Implementation for reconnections
Fixed some tests
Fixed test compilation errors and a test error
Rename ExponentialReconnectionPolicy to ExponentialReconnectionSettings
Add support for maximum attempts in the reconnection settings
Refactor RedisSpecBase to use the Akka TestKit

Reference: http://doc.akka.io/docs/akka/2.3.0/scala/testing.html
Update ClientSpec to test no reconnection and reconnection policies
Organize imports
Add akka-testkit to the dependencies
Revert unconnected logic
Reconnect more quickly during tests
More reliable client termination. Now kills the most recent redis client
Switch to lazy reconnection schedule