/**
* This method takes a new Tile object as argument, and in addition to the functionality of <code>
* addTile()</code>, sets the id of the tile to -1.
*
* @see TileSet#addTile(Tile)
* @param t the new tile to add.
*/
public void addNewTile(Tile t) {
t.setId(-1);
addTile(t);
}
