Remove RelevantHistoryFigure

Whether or not a move is the first move should be tracked for all
pieces, whether or not it is relevant.
Before committing move, record that moved figure has been moved
Implement King.in_check(), make Fields aware of neighbors

Each Player can now look up the other Player. The King looks at each of
the other Player's Pieces and tests if its own Position is in its
legal_moves. If yes, the King is in_check.

Also, fields can now find their immediate neighbors by direction. I wanted to
put this on a separate commit, but I accidentally amended it into this commit
and now I'm too lazy to remove it.
Quick method rename
Implement movement for queen

This also uses a more generalized method on Figure, which accepts direction
strings and uses them to call location awareness methods on Fields. A maximum
movement perimeter can be provided. This method can be reused by almost every
other piece on the board.
Implement basic movement for all pieces.

Special behavior for Kings and Pawns is missing.