Bukkit

• New command /wb bypass [player] [on/off] which enables bypass mode for a player, allowing them to go beyond the border without being knocked back. Requires worldborder.bypass permission to use this command (Ops only by default, included in worldborder.* permission set). The list of people with bypass mode enabled is wiped on server restarts. Specifying [player] name is optional if run in-game and defaults to the player running the command if not specified, but is otherwise required if run from console. Specifying [on/off] is optional and will simply toggle if you don't specify "on" or "off". Thanks to st-remy and guyag for pull requests with basic permission-based border bypass methods which prodded me into making a more comprehensive approach.
• Added artificial height limit for Nether worlds, to work around CraftBukkit bug which reports a max height of 255 for them. This bug otherwise can lead to players being teleported on top of the "roof" of the Nether at height 127.
• Knockback can now be set to 0, for the rare person that might for whatever reason want to disable border knockback.
• Fix for the command which enables/disables Dynmap border display not reporting correctly whether it's enabled or disabled when run.

New command:
/wb bypass [player] [on/off] - enable bypass mode for a player to let them move beyond the border

New permission:
worldborder.bypass (Op): Can use the bypass command to allow specified players beyond the border