We're planning to add support for importing ontologies from several different formats, including RDFS and OWL. Exactly when we'll launch it isn't determined yet as we're in the middle of updating the roadmap, but at the moment sometime in the summer looks like a good estimate, but this might change both ways.
Exporting the ontology to OWL or RDFS isn't something we have a very high priority on at the moment, but if you could give us some examples on situations where that might be useful, we might prioritize differently.