Qt4 - Open and Streaming Dialogs.

Qt4 - Open and Streaming Dialogs.
This commit should show the correct dialogs in the correct order. It keeps the previous behaviour of the "Streaming" from the "Media" menu.
/!\ The intelligence is surely not accurate and stream() may need to be redirected to playOrEnqueue as open() and enqueue() do in order to be correctly parsed before... Need a bit more knowledge on playlist to be sure.