SetHidden fix (player object)

If you use set a Player object or any object derived from it like AIPlayer to hidden in the engine, the engine will crash due to it still doing collision checking on the hidden objects.

Simple fix I found was adding this to the processTick function in the Player.cc file;

void Player::processTick(const Move* move)
{
// If this object is hidden, return
if (isHidden())
return;

(...)
}


Hope this helps anyone having problems with the hidden feature.