Many changes to WithinDocCoref2

 - CorefGazetteers is no longer used and deprecated
 - Training & testing files are passed as command-line arguments
 - It uses the default factorie wordnet (which can be overriden with a system property)

These changes go towards making WithinDocCoref2 fit better in the factorie NLP model, and to having a default trainer for it in the nlp resources repo.