The 4.x version will store a libvlc_media_track_t instead of all its
fields, which is now possible since the track structure is refcounted.
This will also allow us to provide the original tracks back to any
libvlc function that might require it.
The 3.x version will stick to copying each field to the MediaTrack class
since the original libvlc_media_track_t is released as soon as we're
done constructing a MediaTrack vector

It only needs a const libvlc_title_description_t*.

When move-assigning, or copy-assigning, any object that holds an event
manager & inherits from Internal will have the internal class
copy/move constructed first, causing its internal shared pointer to
be overriden, and in turn the libvlc object to be released.
This is a problem if this object contains an event manager with
registered events, as the event manager will be overriden afterward,
causing its destructor to unregister the events after the libvlc
object it needs to unregister the events has been released.

This commit ensures we hold on to the object associated with the event
manager, and that we explicitely unregister all events before releasing
the object.

The actual API wasn't exposed, so let's not bother with having the event
available for 3.0

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>