Tictactoe cleanup

[AntwanAbboud]

What i changed:

• I changed the winner function. I removed the if statements that were checking winning conditions and added a list with all possible winning conditions to see if the board contained any of them. Then, it also checks what the first box (if not empty) in the matching winning condition contains (X or O).
• I changed the first move that the AI plays. It always took around 5 seconds to play its first move since it had to check all the outcomes through the minimax system. This is not efficient on the first move since it always plays the same move (if it moves first). So, I added an if-statement to check if the board was empty, in which case the AI makes a specific move.
• Some minor repetitions that i resolved