Added a simple GUI, that shows the grid in a panel.

Added a generate button. Added a small and imperfect logic to wait for for user input before showing the solved sudoku.

TODO: 1. Perfect the solver.
2. Add preset detection functionality.
3. Add Generate button functionality.
4. Add a way to add presets before generation.
5. Read a Sudoku save file of sorts.
6. Try solving it before seeing solved answer.
     Maybe a 1-9 dropdown to try numbers.
7. Simple greater or lesser hints while solving for each square.
8. A text box underneath that depicts logs and messages.