tmux/i3: Switch sharpshooter toggler to i3
util: Fix dmenu bug

Don't print the $ret multiple times, use the %n$s syntax of printf to repeat
values instead.
i3/tmux: tmuxify the i3 config

Since I only use a browser and a single tmux session, I can use all the Mod4
bindings to manipulate tmux, making manipulating keystrokes even faster than
before.

This also removes the i3 bar and all borders and colors. Everything is now
essentially fullscreen in the same workspace.
vim: Add new Switch() binding