Fill process (/wb fill) can now skip over chunks which are already fully generated, so existing worlds where much of the world is already generated should get through the fill process much faster.
Fill process should run much more smoothly regardless of what frequency you've specified.
If the fill process is automatically paused due to low memory, it now tries to prod Java into cleaning up memory, so the process usually starts right back up almost immediately.
A few other minor tweaks to improve the fill process.
For border crossings where a safe location just inside the border can't be found, the player is now teleported to the spawn location for the current world instead of for the main world.
Removed direct Permissions plugin support. Now permissions are solely handled directly through Bukkit's built-in "superperms" permission system, since all modern permission plugins should now be interfacing through that.
For /wb fill and /wb trim, "stop" can now be used interchangeably with existing "cancel" directive. (i.e. "/wb fill stop" == "/wb fill cancel")