Changed the place where win is counted. Now, there is a new function called win which returns 10, -10, 0 if player wins, cpu wins or it is a draw respectively. It is done for cpu finding best move purposes.
Added cpu_move function which calculates cpu moves. Also added cpu_move calls when player move has been completed
Fixed cpu_move function. best_cpu_move was given a list not an integer
Fixed cpu_move function so that board is passed not by reference
Fixed cpu_move so that board copy is created before for cycle