Fix setting output/device for Xine and VLC backend

- Fixed setting output and device on Xine and VLC backend
- Fixed track slider for Xine, VLC and Phonon
- Improved backend settings to better support multiple backends
- Added group by samplerate and bitdepth in collection
- Fixed crash on exit when existing instance of the application is already runnung caused by NVIDIA driver
- Changed Q_OS_MAC to Q_OS_MACOS

src/engine/osxdevicefinder.cpp

@@ -62,7 +62,7 @@ std::unique_ptr<T> GetProperty(const AudioDeviceID& device_id, const AudioObject
 
 
 OsxDeviceFinder::OsxDeviceFinder()
-    : DeviceFinder("osxaudio", "osxaudiosink") {
+    : DeviceFinder("osxaudio", { "osxaudio", "osx", "osxaudiosink"} ) {
 }
 
 QList<DeviceFinder::Device> OsxDeviceFinder::ListDevices() {