upgrade sbt from 0.13.7 to 0.13.9
upgrade sbt from 0.13.7 to 0.13.9

because why not, the sbt build is experimental anyway

slothspot/scala,scala/scala,scala/scala,jvican/scala,martijnhoekstra/scala,felixmulder/scala,felixmulder/scala,lrytz/scala,slothspot/scala,martijnhoekstra/scala,jvican/scala,scala/scala,scala/scala,lrytz/scala,scala/scala,felixmulder/scala,jvican/scala,lrytz/scala,shimib/scala,shimib/scala,jvican/scala,lrytz/scala,felixmulder/scala,slothspot/scala,jvican/scala,jvican/scala,shimib/scala,shimib/scala,lrytz/scala,lrytz/scala,slothspot/scala,felixmulder/scala,slothspot/scala,scala/scala,martijnhoekstra/scala,slothspot/scala,slothspot/scala,martijnhoekstra/scala,martijnhoekstra/scala,felixmulder/scala,felixmulder/scala,shimib/scala,martijnhoekstra/scala,jvican/scala,shimib/scala