Harvest Craft Fix

Make it so crafts that can harvest (i.e. dismantle elevators) to be able to ONLY function if the worldguard flag allows it. It should be false on default. I'm not sure how I can do this, but I know it would require the onHarvest event and some kind of way from stopping the ship. If you could let me know how I could implement this, I'll try and make this feature. 