maze constructor

  public Maze(String fileName) throws FileNotFoundException{
    Scanner scan = new Scanner(new File(fileName));
    cols = Integer.parseInt(scan.next());
    rows = Integer.parseInt(scan.next());

    grid = new Square[rows][cols];

    // remove line break;
    scan.nextLine();

    // read maze configuration
    for(int i=0; i<rows; i++){
      String row = scan.nextLine();
      for(int j=0; j<cols; j++){
        // create a square from the char representation
        SquareType type = SquareType.fromChar(row.charAt(j));
        Square s = new Square(type, i, j);
        grid[i][j] = s;

        // remember the square as "start" if it is the starting point
        if(type == SquareType.START){
          start = s;
        }
        //System.out.print(row.charAt(j));
      }
      //System.out.println();
    }
  }