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/globalshortcuts/globalshortcuts.cpp

@@ -133,7 +133,7 @@ void GlobalShortcuts::Register() {
 }
 
 bool GlobalShortcuts::IsMacAccessibilityEnabled() const {
-#ifdef Q_OS_MAC
+#ifdef Q_OS_MACOS
   return static_cast<MacGlobalShortcutBackend*>(system_backend_)->IsAccessibilityEnabled();
 #else
   return true;
@@ -141,7 +141,7 @@ bool GlobalShortcuts::IsMacAccessibilityEnabled() const {
 }
 
 void GlobalShortcuts::ShowMacAccessibilityDialog() {
-#ifdef Q_OS_MAC
+#ifdef Q_OS_MACOS
   static_cast<MacGlobalShortcutBackend*>(system_backend_)->ShowAccessibilityDialog();
 #endif
 }