Fixing problems detected by pipeline.

 - Correcting some compilation issues that had escaped my local testing.
 - Updating vecOpDemo app, as we removed the factory approach for generation
   of VectorToVectorOperators. It would not like conflict with other ideas
   we are working on, see e.g. issue #146.
23 jobs for mohr/VecOps in 111 minutes and 59 seconds (queued for 3 seconds)