Added background-music-option: "Only selected song". bg-music is played on name/score/highscore screen with selected song.

VocaluxeLib/IBasic.cs

@@ -35,7 +35,7 @@ namespace VocaluxeLib
         void SetBackgroundMusicVolume(int newVolume);
         int GetBackgroundMusicVolume();
 
-        EOffOn GetBackgroundMusicStatus();
+        EBackgroundMusicOffOn GetBackgroundMusicStatus();
 
         int GetPreviewMusicVolume();