- Write down invariants for the window life cycle, especially:
    - When are borders set?  Prove that the current handling is sufficient.

= Release management =

* build and typecheck all XMC
* generate haddocks for core and XMC, upload to xmonad.org
* generate manpage, generate html manpage
* document, with photos, any new layouts
* double check README build instructions
* test core with 6.6 and 6.8
* upload X11/X11-extras/xmonad to hacakge
* check examples/text in use-facing Config.hs
* check tour.html and intro.html are up to date, and mention all core bindings
* bump xmonad.cabal version