Dump more information to 'position' command.

[CGLemon]

First, thank for your cross platform interface. I implement a chinese chess engine without graph interface. This interface is nice so I don't need to implement another graph interface which support UCI/UCCI. It saves me a lot of time.

But some sad things are that it is a lack of some important functions. The chinese chess engine must to know the game move history in order to deal with perpetual pursuit and sixty-move rule. But this interface only show the current board fen. The output result may be influenced by it. Others, It must end if it occur threefold repetition. Adding more information to 'position' command can solve this issues. Hope that you could fix the issues.