This software should allow the playback of MP3 files. The supported functionalities should be:
1. Play. Starts the playback of an MP3.
2. Stop. Stops the playback of the song and sets the cursor to the beginning of the file.
3. Play/Pause. Starts or pauses the playback of the *.mp3 file.
4. Next. Plays the next song in the list.
5. Previous. Plays the previous song in the list.
6. Volume control.
7. Add file/folder to playlist.
8. Randomize/shuffle play list (when playing)
9. Drag music in list to change playlist order
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The central part of the window should display the playlist, which contains the songs added either via drag and drop or via the add file/folder option.