Overlay JDK
cedar is default
Merge pull request #28 from heroku/cedar-default

cedar is default
set compile time java opts to -Xms768M -Xmx1024M -XX:MaxPermSize=512M -XX:+CMSClassUnloadingEnabled
change play 2.0 to 2.x
Merge from upstream
Add sbt 0.12.2-RC2 compatibility
Merge branch 'play-2.1-RC2'