Improvments to gstreamer backend and settings +++

- Fixed bug not setting environment for gstreamer before initialization
- Fixed windows directsound device
- Fixed crash on failure to create gstreamer element
- Fixed crash when switching backend
- Don't stop playback if equalizer or replay gain fails in gstreamer
- Improvments to backend settings
- Fixed backend settings to work for windows
- Fixed replay gain settings not working
- Fixed right click menu for album showing in statusview even when no song was playing
- Removed redundant code

src/engine/enginedevice.h

@@ -41,9 +41,6 @@ class EngineDevice : public QObject {
   void Init();
   
   QList<DeviceFinder*> device_finders_;
-
- protected:
-  //static QString GuessIconName(const QString &, const QString &);
   
  private:
   QString output_;