A few changes for the sound nameing/themeing specs

[Lennart Poettering]

Heya!

I've made a few changes to the sound theme/naming specs based on requests
from Bastien:

- Document the __custom theme that is used by Bastien's new g-s-p for
  dynamically replacing/disabling sounds in inherited themes.

- Introduce that we check for .disabled pseudo-sounds to allow
  disabling sounds a theme inherited from a parent theme.

- Reorder the lookup algorithm so that a child theme can easily
  overwrite sounds from an inherited stream without having sounds for
  all possible locales/output profiles. 

- Document why we chose dialog-error instead of error-dialog as a
  name, although there are arguments for both names.

- Split of a seperate section for input feedback events in s-n-s

- Fix the example in s-t-s

Marc-André, please pull from
git://git.0pointer.de/sound-theme-spec.git.

The new .disable logic is already implemented in libcanberra in git.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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