implementation of item charges and allowance

mustang/src/main/java/org/mustangproject/ZUGFeRD/IZUGFeRDExportableItem.java

@@ -13,7 +13,8 @@ import java.math.BigDecimal;
 public interface IZUGFeRDExportableItem {
 
 	IZUGFeRDExportableProduct getProduct();
-
+        IZUGFeRDAllowanceCharge[] getItemAllowances();
+        IZUGFeRDAllowanceCharge[] getItemCharges();
 
 
 	/**

mustang/src/test/java/org/mustangproject/ZUGFeRD/MustangReaderWriterEdgeTest.java

@@ -251,6 +251,16 @@ public class MustangReaderWriterEdgeTest extends TestCase implements IZUGFeRDExp
       this.product = product;
     }
 
+    @Override
+    public IZUGFeRDAllowanceCharge[] getItemAllowances() {
+        return null;        
+    }
+
+    @Override
+    public IZUGFeRDAllowanceCharge[] getItemCharges() {
+        return null;
+    }
+
   }
 
   class Product implements IZUGFeRDExportableProduct

mustang/src/test/java/org/mustangproject/ZUGFeRD/MustangReaderWriterTest.java

@@ -253,6 +253,16 @@ public class MustangReaderWriterTest extends TestCase implements IZUGFeRDExporta
       this.product = product;
     }
       
+    @Override
+    public IZUGFeRDAllowanceCharge[] getItemAllowances() {
+        return null;        
+    }
+
+    @Override
+    public IZUGFeRDAllowanceCharge[] getItemCharges() {
+        return null;
+    }    
+
   }
 
   class Product implements IZUGFeRDExportableProduct