Chainable callbacks

[maartenJacobs]

As I was writing wp-notifications-growling, I noticed that we had left out the Notification property callbacks, out of the chainable functions.
In code, that means this is the norm:

$notification = $factory->generateNotification()
                        ->setMessage(htmlspecialchars($message))
                        ->setTo('uids', array($user_id));
$notification->callbacks = $default_callback ? $default_callback : $this->default_callback;
$notification->store();

But in reality, it should have a similarly chainable interface. For instance:

$notification = $factory->generateNotification()
                        ->setMessage(htmlspecialchars($message))
                        ->setTo('uids', array($user_id));
                        ->setCallbacks($default_callback ? $default_callback : $this->default_callback)
                        ->store();

This helps us prevent breaking the chain, and the ease of use.

[maartenJacobs]

The same actually counts for updating a notification. The current API allows the following:

$new_message = 'This message is obsolete. Please remove this call!';
foreach ($factory as $notification) {    
      $notification->setMessage($new_message);
      $factory->updateNotification($notification->getId(), $notification);
}

A better approach would be:

$new_message = 'This message is obsolete. Please remove this call!';
foreach ($factory as $notification) {    
      $notification->setMessage($new_message)->save();
}

As every notification has a reference to the factory it is assigned to, we can actually achieve this.
Any thoughts on this, @didlix? I mean, we will have to alter the base modules for the frameworks we support (which is only WordPress for the moment).