feature request: allow setting tab bar position / vertical tabs

If Mousepad allowed me to position the tab bar on the left or right side of the window (or even just the left side) and listed the tabs vertically when I did so it would allow me to make better use of my screen real estate.

Since the tab bar is a list of tabs it makes sense, in my opinion, to allow it to be vertical. Lists are often taller than they are wide.