Merge remote-tracking branch 'origin/5.4' into 5.5

Conflicts:
	src/multimedia/playback/playlistfileparser.cpp
	src/plugins/windowsaudio/qwindowsaudiodeviceinfo.cpp

Change-Id: I52950def2b8283ae15797d05d4ead6a1256eba19

src/imports/audioengine/qdeclarative_audiosample_p.cpp

@@ -106,6 +106,11 @@ void QDeclarativeAudioSample::componentComplete()
     m_complete = true;
 }
 
+/*!
+    \qmlproperty url QtAudioEngine::AudioSample::source
+
+    This property holds the source URL of the audio sample.
+*/
 QUrl QDeclarativeAudioSample::source() const
 {
     return m_url;