Reverting "String: toLong, List: map(Rep[T=>U]), mkString(sep)."
Does not compile. Please make sure changes compile and pass tests before
pushing to the repo.

This reverts commit 67f3c8dce3963ab44129bf3008907807c54fbfed.
tests comply to code
Merge branch 'develop' of github.com:TiarkRompf/virtualization-lms-core into develop