[merge request] Many minor improvements.

[Teika Kazura <teika lavabit com>]

Hi, please merge my Sawfish branch. It includes:

* resize-window-to-dimensions is split into resize-window-prompt
  and resize-window-to-preset-size (and two more).
* apps-menu & minor doc.
* All hooks are initialized to nil.
* toggle-or-exec cleanup. No user visible change except iconification
  animator. (Use matcher instead.)

Best regards,
Teika (Teika kazura)