Merge pull request #7 from mgarcir/mgarcia/fixes-default-context-on-v…

…alidateobjectattribute

Add default context on ValidateObjectAttribute when is Null

HermaFx.DataAnnotations/ValidateObjectAttribute.cs

@@ -83,6 +83,7 @@ private IEnumerable<ValidationResult> ValidateProperties(object value, Validatio
 
 		protected override ValidationResult IsValid(object value, ValidationContext context)
 		{
+			context = context ?? new ValidationContext(value);
 			var seen = TryGetSeenHashFrom(context);
 
 			//_Log.DebugFormat("Trying to validate {0}", value.ToString());