Create consistent value for draw
Create consistent value for draw

The modulus calculation was leftover from a first attempt at forcing
both players to value a draw the same. Now, with the is_draw member of
Game_Tree_Node_Result and Alpha_Beta_Value, this calculation is not
needed.

MarkZH/Genetic_Chess,MarkZH/Genetic_Chess,MarkZH/Genetic_Chess,MarkZH/Genetic_Chess,MarkZH/Genetic_Chess