Add callback (hook) for adding or removing dirty state on DS.Model

[shwoodard]

In the event of a custom transform like, 'object' that serializes/deserializes json it would be helpful/needed to add the ability to detect if that object is dirty. IOW, just because the objects are the same or not the same does not compare the properties therein.

For example, if I change the value of a property in an 'object' attr and set the attr to a new object--making it dirty--then if I change the property back in a similar fashion, the attr is still dirty because it is not the same object as the original.

[sly7-7]

@shwoodard Is this still relevant ? Probably because I'm not a native english, but I don't understand what you want here.