model changes are propagates for all changes to an entry

MacPass/MPModelChangeObserving.h

@@ -0,0 +1,17 @@
+//
+//  MPModelChangeNotification.h
+//  MacPass
+//
+//  Created by Michael Starke on 30/08/16.
+//  Copyright © 2016 HicknHack Software GmbH. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@protocol MPModelChangeObserving <NSObject>
+
+@required
+- (void)willChangeModelProperty;
+- (void)didChangeModelProperty;
+
+@end