Move public interface and dependent classes from jaggr-service to

jaggr-core.

Moved the files BooleanFormula.java, Formula.java, Term.java and ModuleBuildFuture.java out of impl and over to jaggr-core since they are used by the public interface.

Temporarily increased the visibility of DependencyList.processDeps() to allow unit tests to pass.  Will reduce back to package private after unit tests have been migrated to jaggr-core.