don't put Scala jars on forked boot classpath by default
don't put Scala jars on forked boot classpath by default

Ideally, Scala jars on the normal classpath would be moved to the boot classpath,
but this is more involved.

xeno-by/old-scalameta-sbt,xuwei-k/xsbt,mdedetrich/sbt,mdedetrich/sbt,dyx/sbt,sbt/sbt,xeno-by/old-scalameta-sbt,xeno-by/old-scalameta-sbt,Sciss/sbt,sbt/sbt,dyx/sbt,xeno-by/old-scalameta-sbt,xeno-by/old-scalameta-sbt,corespring/sbt,sbt/sbt,twitter-forks/sbt,Duhemm/compiler-bridge,sbt/sbt,pocketberserker/sbt,twitter-forks/sbt,xuwei-k/xsbt,mdedetrich/sbt,adriaanm/sbt,xuwei-k/xsbt,mdedetrich/sbt,dyx/sbt,jkinkead/sbt,jaceklaskowski/sbt,mdedetrich/sbt,mdedetrich/sbt,jaceklaskowski/sbt,som-snytt/xsbt,mdedetrich/sbt,jkinkead/sbt,xeno-by/old-scalameta-sbt,jasonchaffee/sbt,Duhemm/sbt,sbt/sbt,dyx/sbt,jaceklaskowski/sbt,twitter-forks/sbt,jaceklaskowski/sbt,Duhemm/sbt,xuwei-k/xsbt,sbt/sbt,jkinkead/sbt,pdalpra/sbt,dansanduleac/sbt,twitter-forks/sbt,jkinkead/sbt,jaceklaskowski/sbt,sbt/sbt,twitter-forks/sbt,xuwei-k/xsbt,dyx/sbt,jkinkead/sbt