Reprint and Printed bill editing logged.

Printed bill can no longer be changed, any changes voids the bill and prints a new one.
Added option to Split Bill.
Kot printed with right time.
Numerous bug fixes.

Tanshu.Accounts.Contracts/Data Contracts/ReprintBO.cs

@@ -0,0 +1,13 @@
+using System;
+using Tanshu.Accounts.Entities.Auth;
+
+namespace Tanshu.Accounts.Entities
+{
+    public class Reprint
+    {
+        public virtual int ReprintID { get; set; }
+        public virtual User User { get; set; }
+        public virtual DateTime Date { get; set; }
+        public virtual Voucher Voucher { get; set; }
+    }
+}

Tanshu.Accounts.Contracts/Data Contracts/VoucherBO.cs

@@ -8,27 +8,56 @@ namespace Tanshu.Accounts.Entities
 {
     public class Voucher
     {
-        public Voucher()
+        protected Voucher()
         {
             Kots = new List<Kot>();
             Settlements = new List<VoucherSettlement>();
         }
 
-        public virtual int VoucherID { get; set; }
-        public virtual DateTime? Date { get; set; }
+        public Voucher(User user)
+            : this()
+        {
+            this._date = null;
+            this.User = user;
+        }
+
+        protected int _voucherID;
+        public virtual int VoucherID
+        {
+            get { return _voucherID; }
+        }
+
+        protected DateTime? _date;
+        public virtual DateTime? Date
+        {
+            get { return _date; }
+        }
+
         public virtual string Narration { get; set; }
 
         [NotNull]
         public virtual User User { get; set; }
 
+        protected DateTime _creationDate;
         [NotNull]
-        public virtual DateTime CreationDate { get; set; }
+        public virtual DateTime CreationDate
+        {
+            get { return _creationDate; }
+        }
 
+        protected DateTime _lastEditDate;
         [NotNull]
-        public virtual DateTime LastEditDate { get; set; }
+        public virtual DateTime LastEditDate
+        {
+            get { return _lastEditDate; }
+        }
 
+        protected string _billID;
         [NotNull]
-        public virtual string BillID { get; set; }
+        public virtual string BillID
+        {
+            get { return _billID; }
+        }
 
         [NotNull]
         public virtual string TableID { get; set; }
@@ -48,11 +77,33 @@ namespace Tanshu.Accounts.Entities
         [AllowNull]
         public virtual string VoidReason { get; set; }
 
-        [NotNull]
-        public virtual bool Printed { get; set; }
+        protected bool _printed;
 
         [NotNull]
-        public virtual string KotID { get; set; }
+        public virtual bool Printed
+        {
+            get
+            { return _printed; }
+            set
+            {
+                if (_printed)
+                    return;
+                if (value == false)
+                    return;
+                _date = null;
+                _printed = value;
+            }
+        }
+
+#pragma warning disable 649
+        private string _kotID;
+#pragma warning restore 649
+
+        [NotNull]
+        public virtual string KotID
+        {
+            get { return _kotID; }
+        }
 
         [Cascade]
         public virtual IList<Kot> Kots { get; set; }