Changes to media probing API.

Added flush signals.

Change-Id: I9c124317e843c9b9011e69c44649ae9a4e974161
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>

src/multimedia/video/qvideoprobe.h

@@ -69,6 +69,7 @@ public:
 
 Q_SIGNALS:
     void videoFrameProbed(const QVideoFrame &videoFrame);
+    void flush();
 
 private:
     QVideoProbePrivate *d;