python-chess v0.5.0

New in this release:

• PGN parsing is now more robust: read_game() ignores invalid tokens.
  Still exceptions are going to be thrown on illegal or ambiguous moves, but
  this behaviour can be changed by passing an error_handler argument.

  >>> # Raises ValueError:
  >>> game = chess.pgn.read_game(file_with_illegal_moves)
  
  >>> # Silently ignores errors and continues parsing:
  >>> game = chess.pgn.read_game(file_with_illegal_moves, None)
  
  >>> # Logs the error, continues parsing:
  >>> game = chess.pgn.read_game(file_with_illegal_moves, logger.exception)
  

  If there are too many closing brackets this is now ignored.

  Castling moves like 0-0 (with zeros) are now accepted in PGNs.
  The Bitboard.parse_san() method remains strict as always, though.

  Previously the parser was strictly following the PGN spefification in that
  empty lines terminate a game. So a game like

  [Event "?"]
  
  { Starting comment block }
  
  1. e4 e5 2. Nf3 Nf6 *
  

  would have ended directly after the starting comment. To avoid this, the
  parser will now look ahead until it finds at least one move or a termination
  marker like *, 1-0, 1/2-1/2 or 0-1.

• Introduce a new function scan_headers() to quickly scan a PGN file for
  headers without having to parse the full games.

• Minor testcoverage improvements.