Generify HalloweenGizmo, add global purchase perm

Lobby/src/main/java/tc/oc/lobby/bukkit/gizmos/halloween/horse/HeadlessHorsemanGizmo.java

@@ -35,11 +35,6 @@ public class HeadlessHorsemanGizmo extends HalloweenGizmo implements Listener {
         Bukkit.getPluginManager().registerEvents(this, Lobby.get());
     }
 
-    @Override
-    public boolean canPurchase(Player player) {
-        return player.hasPermission("lobby.gizmo.buy.horse") || player.isOp();
-    }
-
     @EventHandler(ignoreCancelled = true)
     public void onPlayerInteract(PlayerInteractEvent e) {
         if(!(Gizmos.gizmoMap.get(e.getPlayer()) instanceof HeadlessHorsemanGizmo)