Add some battery status icons name to the icon-naming-spec specification

[Javier Jardón]

Hello,

The current specification [1] only has:

 - battery-caution
 - battery-low

I'd like to propose to add:

 - battery-caution-charging
 - battery-empty
 - battery-full
 - battery-full-charged
 - battery-full-charging
 - battery-good
 - battery-good-charging
 - battery-low-charging
 - battery-missing

I've submitted some patches in this bug report: [2]

[1] http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html
[2] https://bugs.freedesktop.org/show_bug.cgi?id=41458

-- 
Javier Jardón Cabezas