Sudoku

Program a sudoku solver.

Todo list: 0. Create a file representation (See Issue #1)

1. Read-in a game (See file 'sudoku_read_file.py') 2.0 Print the game to std_out (See file 'sudoku_show_read_file.py')
   2.1 Create a GUI 2.1.1 Create a GUI - with a single cell 2.1.2 Create a GUI - with a cell (3x3) group 2.1.3 Create a GUI - with of nine cell groups (3x3)
2. Create a data representation
3. ...