Make number-of-moves logic symmetrical in evaluation function

[OyvindSabo]

The bot increases its board score if it has many available moves, but its opponent is valued negatively if the bot has many available moves. This isn't necessarily wrong, but I'd prefer a symmetrical evaluation function.

[OyvindSabo]

Right now the number of moves evaluation has been removed, since it was a bit slow. I would like to bring it back in the future though.

[OyvindSabo]

I realize that it might actually be important that this evaluation is symmetrical, otherwise, when the bot just counts its own number of moves, it might avoid doing a sacrifice, even if that's the best move.

[OyvindSabo]

Also, it is worth noting that it is smart to sacrifice number of available moves if it reduces the opponent's available moves even more.