Dependencies upgrade (Akka, SBT, Scala, SCoverage, ...)

Hi Valerian :)
Here is a PR to upgrade most of Rediscala's dependencies, notably Akka.

Upgraded
* SBT from version 0.12.4 to 0.13.2
* Scala from 2.10.2 to 2.10.4
* Akka from 2.2.1 to 2.3.2
* SCCT from unmaintained version to SCoverage (v0.95.7, and its Coveralls plugin 0.0.5)
* SBT Unidoc from 0.1.1 to 0.3.1

Changed Rediscala version from 1.3 to 1.3.1

About 10 tests are failing, but situation seems to be the same in `etaty:master`