show the variation move numbers perhaps as a toggle in "clean" mode

[amj]

When you're partway down a variation tree, it can be nice to see the numbering from where it diverged from the main line.

Perhaps similar to the 'clean' mode that hides the variations, it'd be a 3 way toggle to show just the variation we're exploring.

("variation" here means the one visible on the game tree widget displayed in minigui)