Improvements in the AI Player's find_best_move function
Added logic to check for the forfeit of turn in find_best_move;
Make the minimax faster; (previously -> 2-4 seconds per move, now-> 1-3 seconds per move) [Start to Mid game].
Fast in the end game as usual.
Refactor code in setup.py
Now, Discs on board and the Game Score update at each move (in single player mode as well).
Place the switch themes logic into a separate method.