Removing PropertyValues-method from Content and Media and making it an extension method instead.

Adding the PropertyEditor model as internal to slowly adopt it using a slightly different model approach then in v5.
Minor refactoring of IEntity/Entity.

src/Umbraco.Core/Models/ContentExtensions.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Linq;
+
+namespace Umbraco.Core.Models
+{
+    public static class ContentExtensions
+    {
+        /// <summary>
+        /// Set property values by alias with an annonymous object
+        /// </summary>
+         public static void PropertyValues(this IContent content, object value)
+         {
+             if (value == null)
+                 throw new Exception("No properties has been passed in");
+
+             var propertyInfos = value.GetType().GetProperties();
+             foreach (var propertyInfo in propertyInfos)
+             {
+                 //Check if a PropertyType with alias exists thus being a valid property
+                 var propertyType = content.PropertyTypes.FirstOrDefault(x => x.Alias == propertyInfo.Name);
+                 if (propertyType == null)
+                     throw new Exception(
+                         string.Format(
+                             "The property alias {0} is not valid, because no PropertyType with this alias exists",
+                             propertyInfo.Name));
+
+                 //Check if a Property with the alias already exists in the collection thus being updated or inserted
+                 var item = content.Properties.FirstOrDefault(x => x.Alias == propertyInfo.Name);
+                 if (item != null)
+                 {
+                     item.Value = propertyInfo.GetValue(value, null);
+                     //Update item with newly added value
+                     content.Properties.Add(item);
+                 }
+                 else
+                 {
+                     //Create new Property to add to collection
+                     var property = propertyType.CreatePropertyFromValue(propertyInfo.GetValue(value, null));
+                     content.Properties.Add(property);
+                 }
+             }
+         }
+    }
+}