Don't do econ stuff when econ features are disabled

src/com/massivecraft/factions/engine/EngineEcon.java

@@ -50,6 +50,8 @@ public class EngineEcon extends Engine
 	@EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
 	public void takeOnLeave(EventFactionsMembershipChange event)
 	{
+		if (!Econ.isEnabled()) return;
+		
 		// If a player is leaving the faction ...
 		if (event.getReason() != MembershipChangeReason.LEAVE) return;