Missing docs for ProjectRef & RootProject

[benmccann]

I don't see ProjectRef or RootProject mentioned anywhere in the documentation. A good place to include these docs might be in the section for multi-project builds.

I have a lot of questions about how to setup multi-project builds as our codebase grows larger. Should we put our entire codebase in a single SBT build split amongst standard SBT sub-projects? Or should we make each library it's own SBT project and wire them all together with ProjectRef external references?

[benmccann]

Discussion of this topic: https://groups.google.com/forum/#!topic/sbt-dev/pTmZ8dCnjBs

[coreyoconnor]

I propose introducing the functionality as "An experimental implementation of external source dependencies" and then link to the sbt ticket (???) for defining the expected behavior. That would assist on collecting expectations.