TODO

   1 PROBABLY WON'T FIX:
   2 Embedded rules language not updated when language is set (in Analyse, Game and Problems)
   3 If new live game starts in background, "new game" notify OK but not first move.
   4
   5 "FreeBoard", re-using a lot of Board logic, but with SVG (empty) board + SVG (empty) reserves.
   6 Will be used for variants with custom non-rectangular board (Hex, at least)
   7 Or, with other board shapes (see greenchess.net for example)
   8
   9 =====
  10
  11 New variants:
  12 Hidden2: Hidden with free initial setup (as in Screen)
  13 Shinobi Chess