Put in some more signals and slots/rearranging of playlistmanager
I made mpv handler just a QObject rather than a QFrame like it was, now we just pass the windows id to MpvHandler effectively making it no longer a widget (to please my peer). Similarly because playlistmanager is they same type of object as MpvHandler, I'm now passing the playlistWidget to the manager which is no longer a widget. Also added some slots/signals in the constructor and comments to show how i'm organizing the big list of connect calls.