Unit tests covering the ContentService.

Adding new configurations to the release configs.
Refactoring the publishing strategy and a few of the services.

src/Umbraco.Core/Models/Property.cs

@@ -98,8 +98,8 @@ namespace Umbraco.Core.Models
                 if (!typeValidation)
                     throw new Exception(
                         string.Format(
-                            "Type validation failed. The value type: {0} does not match the DataType in PropertyType with alias: {1}",
-                            value.GetType(), Alias));
+                            "Type validation failed. The value type: '{0}' does not match the DataType in PropertyType with alias: '{1}'",
+                            value == null ? "null" : value.GetType().Name, Alias));
 
                 _value = value;
                 OnPropertyChanged(ValueSelector);

src/Umbraco.Core/Models/PropertyType.cs

@@ -256,6 +256,9 @@ namespace Umbraco.Core.Models
         /// <returns>True if valid, otherwise false</returns>
         public bool IsPropertyTypeValid(object value)
         {
+            if (value == null)
+                return false;
+
             //Check type if the type of the value match the type from the DataType/PropertyEditor
             Type type = value.GetType();