New Puzzle: Chess Mazes

I've seen two different styles of chess maze by [David Johnson-Davies] and Bruce Albertson. I think I prefer Bruce's style, because the moves are reversible, and it feels closer to chess. Here's a brief summary:

* Start position shows one white piece, black king, and any number of other black pieces.
* Goal is to put the black king in check.
* If a black piece can ever capture the white piece, they immediately do so, and you lose. Otherwise, black pieces never move.
* The white piece may make any legal chess move.

Try generating some puzzles, to see if they're interesting.

* [ ] Write a solver.
* [ ] Generate random layouts, and print longest solution.
* [ ] Score based on solution length and uniqueness.
* [ ] Use evolutionary search.
* [ ] Increase score for more black pieces.
* [ ] Penalize score for unneeded black pieces.
* [ ] Increase score for more board coverage.
* [ ] Other scoring, like branching structure?

[David Johnson-Davies]: http://www.mazelog.com/show?9

Start with the unchecked solver and puzzle-generation goals in the issue, then review the repository to locate the existing chess-move and board-generation entry points. Done means producing chess-maze layouts with solutions and evaluating them using the listed length, uniqueness, piece, coverage, and branching criteria.

Written by the indexing model from the issue text.