Play 2.2: fix deprecation warnings and update SBT settings

This should complement (or supercede) #281, including more fixes to work with Play 2.2. It fixes deprecated uses of PlainResult (only SimpleResult is supported now), cleans up all SBT configurations to .sbt files over Scala source code, cleans up repository references, and corrects the version tag to 'master-SNAPSHOT' (but I believe creating a new 2.2.x branch would be a good idea).