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.cpp

@@ -81,7 +81,7 @@ void EngineDevice::Init() {
 
   for (DeviceFinder *finder : device_finders) {
     if (!finder->Initialise()) {
-      qLog(Warning) << "Failed to initialise DeviceFinder for" << finder->output();
+      qLog(Warning) << "Failed to initialise DeviceFinder for" << finder->name();
       delete finder;
       continue;
     }