[xmonad] Alt-tab behavior

[Michael Orlitzky]

Is there a way to restore "typical" alt-tab behavior (i.e. what most WMs
do by default)? With alt held down, each tab press will cycle forward.
Release alt, press it again, and each tab now cycles backwards through
the list of windows.

What I *really* want from this is just a side effect: alt-tab-(release)
always switches to the "last" window -- the one that was focused before
the current one.

I apparently have this operation burned into my brain, and I attempt to
use it continually throughout the day whether it works or not.