a44cbf2a72
- added a class BackgroundMusic: is an AbstractAppState and GameEventListener that handles the backgroundmusic - attached the BackgroundMusic to the stateManager in the BattleshipApp - added to the Menu a CheckBox and Slider to manipulate the volume of the backgroundmusic - added four different music files (for different states of the game) - edited the WaitState and BattleState to play different music files when chaing to that state - added to ClientGameLogic a new method playMusic(Music) to play the right music (depends on the current state) - added a new method receivedEvent(MusicEvent) to handle the music events - added a new enum Music, that represents different types of music - added a new record MusicEvent(Music), that decides which music shall play