Handle searching more than one ontology

[twhetzel]

The current input file needs to be annotated to Mondo, HP, and MaxO. While each row should be searched to one ontology at a time, it would be useful to be able to pass a list of ontologies to be search sequentially and keeping the existing result logic in place (search one ontology, first exact label, then empty rows against exact synonym... perhaps later other methods added to the sequence). When done with one ontology, search with the next in the list.