Updated Redis for Scala 2.11 compatibility

I haven't updated the version from `2.3.0` or any of the other play dependencies. I thought I would leave that for the maintainers to decide.
If you want to cross build, you need to not specify the scala version - this will cause the 2.11 version to be used both against 2.10 and 2.11, which is wrong.  Instead, use:

    "org.sedis" %% "sedis" % "1.2.2"

Then SBT will pick the right version for the right version of Scala when building.  To test cross building, run `sbt +test` (the + means run this command against all configured cross scala versions).