TODO

   1 Chakart :)
   2
   3 Ambiguous chess
   4 https://www.chessvariants.com/mvopponent.dir/ambiguous-chess.html
   5 Need special highlight square --> similar to enlightened for Dark, in Board.vue
   6 Also in notation, show only dest square for "opponents ambiguous moves".
   7 Similar to Marseille-chess, white first move only 1 subTurn, do not choose a square.
   8 Then black has a free first move, then choose a square, and the process goes on.
   9
  10 Sittuyin (burmese chess)
  11 https://github.com/gbtami/pychess-variants/tree/master/static/images/pieces/sittuyin
  12 https://drive.google.com/open?id=1HIPJLJBU2F6R6vxGziU6j8MHoHu_Kmab