Report the number of unsatisfiable classes after invoking the reasoner

[matthewhorridge]

This is a feature request from Issue #1314

I would like to suggest a new feature for the future release. When debugging a large ontology with numerous unsatisfied terms, often times, fixing a single term would lead to numerous other terms being fixed simultaneously as well. To track when this happens and which 'root' term is responsible, it would be informative to add in the Ontology metrics pane the number of unsatisfied terms whenever a reasoner is invoked.