Update to Freeciv server r24891.
Add support for the achievements dialog.
Fix some Javascript errors reported by Track:js.
Pick nation color based on most common color in flag.
Only run update_player_info() in pregame mode.
Fix size.
Make it possible to join only multiplayer games.
Force updating of metaserver when first player joins server, to tell metaserver not to use this server for other players.
Limit the total number of animated units, for improved performance on games with many units.