python-chess v0.9.0

This is a big update with quite a few breaking changes. Carefully review
the changes before upgrading. It's no problem if you can not update right now.
The 0.8.x branch still gets bugfixes.

Incompatible changes:

• Removed castling right constants. Castling rights are now represented as a
  bitmask of the rook square. For example:

  .. code:: python

  >>> board = chess.Board()
  
  >>> # Standard castling rights.
  >>> board.castling_rights == chess.BB_A1 | chess.BB_H1 | chess.BB_A8 | chess.BB_H8
  True
  
  >>> # Check for the presence of a specific castling right.
  >>> can_white_castle_queenside = chess.BB_A1 & board.castling_rights
  

  Castling moves were previously encoded as the corresponding king movement in
  UCI, e.g. e1f1 for white kingside castling. Now castling moves are
  encoded as a move to the corresponding rook square (UCI_Chess960-style),
  e.g. e1a1.

  You may use the new methods Board.uci(move, chess960=True),
  Board.parse_uci(uci) and Board.push_uci(uci) to handle this
  transparently.

  The uci module takes care of converting moves when communicating with an
  engine that is not in UCI_Chess960 mode.

• The get_entries_for_position(board) method of polyglot opening book readers
  has been changed to find_all(board, minimum_weight=1). By default entries
  with weight 0 are excluded.

• The Board.pieces lookup list has been removed.

• In 0.8.1 the spelling of repetition (was repitition) was fixed.
  can_claim_threefold_repetition() and is_fivefold_repetition() are the
  affected method names. Aliases are now removed.

• Board.set_epd() will now interpret bm, am as a list of moves for the
  current position and pv as a variation (represented by a list of moves).
  Thanks to Jordan Bray for reporting this.

• Removed uci.InfoHandler.pre_bestmove() and
  uci.InfoHandler.post_bestmove().

• uci.InfoHandler().info["score"] is now relative to multipv. Use

  .. code:: python

  >>> with info_handler as info:
  ...     if 1 in info["score"]:
  ...         cp = info["score"][1].cp
  

  where you were previously using

  .. code:: python

  >>> with info_handler as info:
  ...     if "score" in info:
  ...         cp = info["score"].cp
  

• Clear uci.InfoHandler() dictionary at the start of new searches
  (new on_go()), not at the end of searches.

• Renamed PseudoLegalMoveGenerator.bitboard and LegalMoveGenerator.bitboard
  to PseudoLegalMoveGenerator.board and LegalMoveGenerator.board,
  respectively.

• Scripts removed.

• Python 3.2 compability dropped. Use Python 3.3 or higher. Python 2.7 support
  is not affected.

New features:

• Introduced Chess960 support. Board(fen) and Board.set_fen(fen) now
  support X-FENs. Added Board.shredder_fen().
  Board.status(allow_chess960=True) has an optional argument allowing to
  insist on standard chess castling rules.
  Added Board.is_valid(allow_chess960=True).
• Improved move generation using Shatranj-style direct lookup <http://arxiv.org/pdf/0704.3773.pdf>_. Removed rotated bitboards. Perft
  speed has been more than doubled.
• Added choice(board) and weighted_choice(board) for polyglot opening book
  readers.
• Added Board.attacks(square) to determine attacks from a given square.
  There already was Board.attackers(color, square) returning attacks to
  a square.
• Added Board.is_en_passant(move), Board.is_capture(move) and
  Board.is_castling(move).
• Added Board.pin(color, square) and Board.is_pinned(color, square).
• There is a new method Board.pieces(piece_type, color) to get a set of
  squares with the specified pieces.
• Do expensive Syzygy table initialization on demand.
• Allow promotions like e8Q (usually e8=Q) in Board.parse_san() and
  PGN files.
• Patch by Richard C. Gerkin: Added Board.__unicode__() just like
  Board.__str__() but with unicode pieces.
• Patch by Richard C. Gerkin: Added Board.__html__().