Moved numpad control to Tanshu.Common. Billing feature complete. Delete not working as expected

Signed-off-by: unknown <tanshu@.(none)>

Tanshu.Accounts.Contracts/Data Contracts/InventoryModifierBO.cs

@@ -1,13 +1,16 @@
 using System;
 using System.Runtime.Serialization;
 using FluentNHibernate.Mapping;
+using Tanshu.Accounts.Contracts;
 
 namespace Tanshu.Accounts.Entities
 {
     public class InventoryModifier
     {
         public virtual int InventoryModifierID { get; set; }
+        [NotNull]
         public virtual Inventory Inventory { get; set; }
+        [NotNull]
         public virtual Modifier Modifier { get; set; }
     }
 }