Fixes to polyglot code.
Simplify the search in chess-polyglot.el.
Make the strength of book replies configurable.
Pacify byte compiler.
Decompress a polyglot book file if it was compressed.
chess-uci.el: Use the post-move event to work around a display bug when the handler directly replies with a move because it was found in the book.
Provide unicode box drawing characters as a possible choice for chess-plain-border-chars via custom :type.
chess-plain-piece-chars: Provide some useful default settings via custom :type.
chess-plain-piece-chars: Include a suggestion for unicode figures.