[xmonad] Smarter multi-screen layouts (ab)using XRandR

[wagnerdm at seas.upenn.edu]

Quoting Joachim Breitner <mail at joachim-breitner.de>:
> I'd like to have the same workspace on both [screens].

Oh, also, for your particular use-case of presenting, I've used the  
following hack with some success: start a VNC session locally, then  
open two clients and full-screen them, one on the projected workspace  
and one on the presenting workspace.

~d