Just uploaded yet another update. Someone requested the ability to pass in Joseki on the reviews, so I thought I'd go ahead and put it in. You can pass through the options menu, a new button that's only enabled if there's a "pass" in the dictionary for the current move, or if there's a "tenuki spot," which is just some label in the bottom corner without a variation associated.
In other news, I've changed handicaps to follow this page: http://senseis.xmp.net/?path=Handicap&page=HandicapPlacement. I think this is more common. If you don't like those, however, I've also added custom handicap placement.
Finally, I've added a bit more SGF/Tsumego compatibility, and updated the visual area calculation to include labels. Also, if it surrounded the board completely, it now shrinks it back down to what you'd expect.
+ Added passing for Joseki; Clicking on the tenuki spot in Kogo (IE, a label without an associated variation) will also pass
+ Added custom handicap placement!
+ "Automatic" (Japanese) handicaps now match GnuGo's order
+ More compatibility (specifically, old-style multiple labels, board size specifications for tsumego)
* Fix: Visual area for Tsumego now takes labels/annotations into account