Adding JDK7 friendly build with new partialdist(-opt) tasks.
Adding JDK7 friendly build with new partialdist(-opt) tasks.

* When running in JDK 7 issues a warning.
* New partialdist, partialdist-opt tasks allow creating a distribution with no source/docs.

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