python-chess v0.8.0

New in this release:

• Implement Syzygy endgame tablebase probing.
  https://syzygy-tables.info is an example project that provides a public API using the new features.
• The interface for aynchronous UCI command has changed to mimic concurrent.futures. is_done() is now just done(). Callbacks will receive the command object as a single argument instead of the result. The result property and wait() have been removed in favor of a synchronously waiting result() method.
• The result of the stop and go UCI commands are now named tuples (instead of just normal tuples).
• Add alias Board for Bitboard.
• Fixed race condition during UCI engine startup. Lines received during engine startup sometimes needed to be processed before the Engine object was fully initialized.