adds initial commit of entity cloning

src/Umbraco.Core/Models/PropertyCollection.cs

@@ -5,6 +5,7 @@ using System.Collections.Specialized;
 using System.Linq;
 using System.Runtime.Serialization;
 using System.Threading;
+using Umbraco.Core.Models.EntityBase;
 
 namespace Umbraco.Core.Models
 {
@@ -13,7 +14,7 @@ namespace Umbraco.Core.Models
     /// </summary>
     [Serializable]
     [DataContract(IsReference = true)]
-    public class PropertyCollection : KeyedCollection<string, Property>, INotifyCollectionChanged
+    public class PropertyCollection : KeyedCollection<string, Property>, INotifyCollectionChanged, IDeepCloneable
     {
         private readonly ReaderWriterLockSlim _addLocker = new ReaderWriterLockSlim();
         internal Action OnAdd;
@@ -195,5 +196,19 @@ namespace Umbraco.Core.Models
                 }
             }
         }
+
+        /// <summary>
+        /// Create a deep clone of this property collection
+        /// </summary>
+        /// <returns></returns>
+        public T DeepClone<T>() where T: IDeepCloneable
+        {
+            var newList = new PropertyCollection();
+            foreach (var p in this)
+            {
+                newList.Add(p.DeepClone<Property>());
+            }
+            return (T)(object)newList;
+        }
     }
 }