Mediaplayer: does not disable full screen when end of video playlist is reached

QMediaPlayer does not automatically disable full-screen mode when video playback ends. This means that the user sees a black screen, and has to double-tap to get back to the application UI.

This may be fixed when we implement aboutToFinish and/or playlist support. If not, then (at least on Symbian), either the MediaPlayer app or Phonon itself needs to be modified to disable full screen video when the playlist ends.