// The root position. This is set up when the user (or in practice, the GUI)
// sends the "position" UCI command. The root position is sent to the think()
// function when the program receives the "go" command.
// The root position. This is set up when the user (or in practice, the GUI)
// sends the "position" UCI command. The root position is sent to the think()
// function when the program receives the "go" command.