fix dtors

stepmania/src/ScoreKeeper.h

@@ -35,6 +35,7 @@ protected:
 
 public:
 	ScoreKeeper(PlayerState* pPlayerState,PlayerStageStats* pPlayerStageStats) { m_pPlayerState=pPlayerState; m_pPlayerStageStats=pPlayerStageStats; }
+	virtual ~ScoreKeeper() { }
 	virtual void Load(
 		const vector<Song*>& apSongs,
 		const vector<Steps*>& apSteps,

stepmania/src/ScoreKeeperMAX2.h

@@ -34,6 +34,7 @@ public:
 	ScoreKeeperMAX2( 
 		PlayerState* pPlayerState,
 		PlayerStageStats* pPlayerStageStats );
+	virtual ~ScoreKeeperMAX2() { }
 
 	void Load(
 		const vector<Song*>& apSongs,

stepmania/src/ScoreKeeperRave.h

@@ -10,8 +10,8 @@
 class ScoreKeeperRave : public ScoreKeeper
 {
 public:
-	// Overrides
 	ScoreKeeperRave( PlayerState* pPlayerState, PlayerStageStats* pPlayerStageStats );
+	virtual ~ScoreKeeperRave() { }
 	void OnNextSong( int iSongInCourseIndex, const Steps* pSteps, const NoteData* pNoteData );	// before a song plays (called multiple times if course)
 	void HandleTapScore( TapNoteScore score );
 	void HandleTapRowScore( TapNoteScore scoreOfLastTap, int iNumTapsInRow );