-End of game a bit too verbose: should just say "Black win" ... + show PGN
-Styles must be improved (full width for smartphones, selectable text for PGN...)
+For animation, moves should contains "moving" and "fading" maybe...
+(But it's really just for Magnetic chess)
+setInterval "CRON" task in sockets.js to check connected clients
+(every 1hour maybe, or more)
+Button to show all pieces that can move (next to expert mode; change icons)
+Some bots are very weak, others quite slow...