Make win-tab switching show a list of currently open windows.
Created by: ca1ek
How it looks: https://gfycat.com/UnhealthyDistantDesertpupfish
OrbitalScheme has an added variable,
win_tabbing. When the user presses super-tab it's set to true. This makes each call to
draw_window_list(). When super is released,
win_tabbing is set false, window list isn't drawn anymore.