Heroku Changelog SBT 0.13.5 and Play 2.3 Support

Change effective on 11 June 2014

Heroku now supports SBT 0.13.5 for Scala. SBT 0.13.5 also enables Play 2.3 support. Set sbt.version=0.13.5 in your project’s /project/build.properties file to upgrade.