The vertical line feature is sometimes nice for lining things up.
However, it is too hard to configure, and it doesn't do anything.
#1: Make it easy to set vertical lines in the UI (Meta+Click or something to toggle a line).
#2: Make <Tab> jump to the next vertical line
#3: Make it per-window instead of global / all windows.
#4: Make format-columns use align to vertical lines.
