Migrate to Play 2.1

Move riff-raff onto play 2.1 - with much effort also from @philwills and @rtyley 

In the process of migration, more libraries than can be mentioned have been upgraded and the use of both sbt.io and salat has been dropped due to various reflection issues and lack of support for Scala 2.10.

This meant introducing our own mapping code for classes being persisted to the database - but that's no bad thing.