Initial implementation of QML2 VideoOutput element

Change-Id: I5ed00433fe5e993086ae1698b7344c8d60a5f0f6
Reviewed-on: http://codereview.qt.nokia.com/2727
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>
Reviewed-by: Jonas Rabbe <jonas.rabbe@nokia.com>
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>

src/imports/multimedia/qdeclarativeaudio.cpp

@@ -305,6 +305,7 @@ QDeclarativeAudio::Error QDeclarativeAudio::error() const
 void QDeclarativeAudio::classBegin()
 {
     setObject(this);
+    emit mediaObjectChanged();
 }
 
 void QDeclarativeAudio::componentComplete()