Fix Crash when adding trades when items are disabled.

hooks/AETrading.java

@@ -42,6 +42,9 @@ public class AETrading implements IVillageTradeHandler
 
 	private void addMerchent(MerchantRecipeList list, ItemStack item, int emera, Random rand, int greed)
 	{
+		if ( item == null )
+			return;
+		
 		// Sell
 		ItemStack From = item.copy();
 		ItemStack To = new ItemStack( Items.emerald );