[fqbzmtwp] Non repeating endgame demo

A demonstration of somewhat random chess endgame technique.  The winning side makes random moves which preserve the win but not necessarily make progress.  The losing side plays the most stubborn defense.  The winning side tries somewhat to avoid recently seen positions.

Next, try to do this formally perfectly.  The winning side, armed only with a bitbase that does not give distance, must avoid cul-de-sacs in the graph that to make progress require exiting through the same entrance, repeating a position.  The losing side tries to force the other into cul-de-sacs, which might be different from the most stubborn defense.