Add person_appears predicate for ghost
Add person_appears predicate for ghost

Also supporting fuctions used to create the model used by
the predicate.

andre-senna/opencog,AmeBel/opencog,AmeBel/opencog,AmeBel/opencog,AmeBel/opencog,andre-senna/opencog,andre-senna/opencog,andre-senna/opencog,andre-senna/opencog,andre-senna/opencog,andre-senna/opencog,AmeBel/opencog,AmeBel/opencog,AmeBel/opencog