Add listbox stack display
Long ago I implemented a ListBox widget for displaying the stack that allowed you to drag-n-drop items on the stack to rearrange them.
Now that the log and scratch text are combined in one window I think the stack viewer might be a good addition. (Hopefully I can find the old code!)
Found the old code (at least one version of it): https://github.com/calroc/xerblin/releases/tag/oldroot
Checked it out and ran it, it worked without any problems.
xerblin$ PYTHONPATH=. bin/xerblin-fresh
Extracted the list box widget.
It takes a list(-like object) and rearranges it on successful drag. I think the easiest thing to do is just brute convert from stack to list and back as needed. No fancy sync.
Going from the DnD operation to the World is straightforward. Going from the world to the listbox involves overriding the print_stack() method I think.
Still some little issues: