optional data unit in sparql transformer
Merge branch 'master' of github.com:mff-uk/intlib
Merge branch 'master' of github.com:mff-uk/intlib
Merge branch 'master' of github.com:mff-uk/intlib
Merge branch 'master' of https://github.com/mff-uk/ODCS
Merge branch 'master' into mvp