Jar file description for locating jars.
The scala jars split into compiler, library, and extra.
Automatically add the output directory and scala library to the classpath.
Create Inputs based on command-line settings.
Load the analysis for the destination, creating it if necessary.
Select the scala jars.
Select the scala jars.
Prefer the explicit scala-compiler, scala-library, and scala-extra settings, then the scala-path setting, then the scala-home setting. Default to bundled scala.
Distinguish the compiler and library jars.