This module allows dwm-style tagging (as I understand dwm). You can have a
given window visible in multiple workspaces. If it's visible in two
workspaces both of which are visible, a gap will show up in one of them
(which is something that needs fixing in xmonad core). Also defines a
kill1 which is like kill, but only removes from the current workspace a
window if it's in multiple workspaces.
