[TF-ENT] new conditions for RDF(S) solutions

Andy, others,
I reworked the conditions on solutions for RDF and RDFS entailment and
I hope they make more sense now. I added a new example for both RDF
and RDFS entailment that especially considers blank nodes and will
hopefully be helpful in validating whether the current definition
works as we expect. I am still not very clear about blank nodes in
pattern matching, so I am grateful about any comments.
Birte

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Dr. Birte Glimm, Room 306
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