[merge request] Doc & minor changes.

[Teika Kazura]

Hi. Please merge my branch. It includes:
* Doc. Sound support, shutdown / reboot / others.
* sawfish-client.jl won't say "bye" at exit. 
  (Sorry, it was me who put this, but it annoys if you use 
  Emacs' sawfish-mode.)

Regards,
Teika (Teika kazura)