fix reloading: simply calling LoadFromSMFile won't reset everything,

leading to duplicate notes and some other stuff not always being reverted

stepmania/src/ScreenEdit.cpp

@@ -1110,7 +1110,7 @@ void ScreenEdit::HandleScreenMessage( const ScreenMessage SM )
 	{
 	case SM_GoToNextScreen:
 		// Reload song from disk to discard changes.
-		GAMESTATE->m_pCurSong->LoadFromSongDir( GAMESTATE->m_pCurSong->GetSongDir() );
+		GAMESTATE->m_pCurSong->RevertFromDisk();
 		SCREENMAN->SetNewScreen( "ScreenEditMenu" );
 		break;
 	case SM_BackFromMainMenu:

stepmania/src/ScreenGameplay.cpp

@@ -1306,14 +1306,12 @@ void SaveChanges()
 
 void DontSaveChanges()
 {
-	SMLoader ld;
 	switch( GAMESTATE->m_PlayMode )
 	{
 	case PLAY_MODE_ARCADE:
 	case PLAY_MODE_BATTLE:
 	case PLAY_MODE_RAVE:
-		ld.LoadFromSMFile(GAMESTATE->m_pCurSong->GetCacheFilePath(),
-			*GAMESTATE->m_pCurSong);
+		GAMESTATE->m_pCurSong->RevertFromDisk();
 		break;
 	case PLAY_MODE_NONSTOP:
 	case PLAY_MODE_ONI: