[Inkscape-devel] Layers dialog

Well, I think we're hitting the home stretch here.

I've folded in most of the main functional changes, including scrolling, pop-up menus, in-place editing of layer names, and not rebuilding the entire tree every time you select a different layer.

Depending on how robust things are, I may be able to add the eye and lock icons, and to switch the status bar's layer selector to use the same layer manager back-end. However, any poking at it people can do in the mean time would be helpful.