OPEN - task 14: extended grammar, but generator doesn't use it yet
OPEN - task 20: extended grammar, but generator doesn't use it yet
OPEN - task 21: extended grammar (excl. JVM), but generator doesn't use
it yet
OPEN - task 22: added expensive validation, that checks existence of
repositories, units and versions as well as if there are newer versions.
In this case a quickfix is provided.