Scala 2.10.1-RC3
fix project/flatten scripted test
Further Scala handling refinements.  fixes #690.

* No longer override the Scala version to force it to be scalaVersion.  Custom configurations might use an independent version.
* Only substitute the jars from scalaHome when the major.minor versions line up for the substituted artifact
* Allow the Scala version to use for dependency resolution to be specified when using ++ to change Scala home: ++ version=/path/to/scala/home