tilesets.add(s);
tilesets.add(tileset);
    public void addTileset(TileSet s) {        if (s == null || tilesets.indexOf(s) > -1) {            return;        }        Tile t = s.getTile(0);        if (t != null) {            int tw = t.getWidth();            int th = t.getHeight();            if (tw != tileWidth) {                if (tileWidth == 0) {                    tileWidth = tw;                    tileHeight = th;                }            }        }        tilesets.add(s);        fireMapChanged();    }