Bukkit

• Added "/cp tp <player>" to teleport to a player playing in a CreativeParkour map and watch it in spectator mode.
  
• Performance improvements.
  
• Players can now accept invitations while being in a map.
  
• Improved some messages.
  
• Fixed an issue with unallowed blocks.
  

About the new sign direction feature in 1.2.1 (players are now facing the same direction as the checkpoint and spawn signs when they teleport to them) :
Sign orientation has not been stored in old maps, consequently, this update will set them to default. To set the orientations you want, you must edit these maps and replace the signs, but scoreboards will be deleted. To avoid this, backup the players_times.yml file somewhere, edit your maps, and when you have finished, replace the new players_times.yml file by the one you backuped and finally, restart your server.