Upgrade to Play 2.3.0-RC2

**Do not merge until we've made a branch for 0.6.x**

This PR is based on @jadlr's work for #152. I've taken his work and updated it to Play 2.3.0-RC2, Slick 2.0.2, Scala 2.10.4 and sbt 0.13.5-RC3.