media list: add missing notification when a media item is added

For non-understood reasons, we always defined and promised that there would be a notification when an item is added to a media list, but we only triggered the delegate and never send the notification in contrast to deleting an item from the list.

You notify the whole NSNotificationCenter when something is added? Is that normal?

This is normal. In contrast to NSDistributedNotificationCenter NSNotificationCenter is for the application loading the framework only, so the notifications are broadcasted in that context only (and in the case of the default notification center, on the main thread only, too).

Ping.

merged

changed milestone to %4.0