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/xinefader.h

@@ -0,0 +1,70 @@
+/***************************************************************************
+ *   Copyright (C) 2017-2018 Jonas Kvinge <jonas@jkvinge.net>              *
+ *   Copyright (C) 2005 Christophe Thommeret <hftom@free.fr>               *
+ *             (C) 2005 Ian Monroe <ian@monroe.nu>                         *
+ *             (C) 2005-2006 Mark Kretschmann <markey@web.de>              *
+ *             (C) 2004-2005 Max Howell <max.howell@methylblue.com>        *
+ *             (C) 2003-2004 J. Kofler <kaffeine@gmx.net>                  *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef XINEFADER_H
+#define XINEFADER_H
+
+#include "config.h"
+
+#include <QtGlobal>
+#include <QThread>
+
+class XineFader : public QThread {
+    
+private:
+
+  XineEngine *engine_;
+  xine_t *xine_;
+  xine_stream_t *stream_;
+  xine_stream_t *decrease_;
+  xine_stream_t *increase_;
+  xine_audio_port_t *port_;
+  xine_post_t *post_;
+  uint fade_length_;
+  bool paused_;
+  bool terminated_;
+  bool stop_fader_;
+
+  void run();
+
+public:
+
+  XineFader(XineEngine *engine, xine_t *xine, xine_stream_t *stream, xine_audio_port_t *audioport, xine_post_t *post, uint fadeMs);
+  ~XineFader();
+
+   void pause();
+   void resume();
+   void finish();
+
+};
+
+class XineOutFader : public QThread {
+    
+private:
+
+  XineEngine *engine_;
+  bool terminated_;
+  uint fade_length_;
+
+  void run();
+
+public:
+  XineOutFader(XineEngine *, uint fadeLengthMs );
+  ~XineOutFader();
+
+   void finish();
+};
+
+#endif