Added SatisfyingSetToConceptRule
Revised ConceptToPredicateLink as PredicateNode

Inside EvaluationLink
Added unit test

Doesn't work yet, though
Small modifications

Rule works in MindAgent now, doesn't yet work in pln unit test though
Fixed merge conflict
Merge pull request #953 from sebastianruder/satisfyingsettoconceptrule

Added SatisfyingSetToConceptRule