Panel icon themeing changes (and more)

[Jasper Huijsmans]

Right, I just added some rather large changes to CVS. It will screw up
people's setup, and I apologise for that.

This is from the CVS log message:
===
Oh dear, big changes. Please test.
Changes include:
* Icon themeing based on icon spec. No more panel-specific theme option.
  Panel themes can still be created, but additionally the panel looks for
  gnome and kde icons, when no xfce- namespaced icons were found.
  Old panel themes will no longer work.
* Removed old icon themes.
* Removed panel layer option. The panel now is a dock-type window and
  sets partial struts to allow the wm to do the right thing.
===

A little explanation. The panel now follows the general icon theme as set 
in the user interface dialog. On startup, or when the theme changes, the 
panel will try to find an appropriate icon in the following order:

1) An xfce-* namespaced icon in the current theme, e.g. xfce-exit

2) Gnome or kde icons in the current theme, e.g. gnome-exit

3) Fallback xfce icon in the hicolor theme (which is actually already 
   returned by the icon lookup in (1)).

Look at the icons/ directory to see the new icon names. The xfce-system-*
icons are 16x16 and the others are 48x48. My goal is to find a good list of
gnome and kde icon names, such that all major icon themes give a fully themed
panel, without having to create special xfce variants of the icons.


Another, possibly controversial, decission I made was to turn the panel into a
dock type window (like gnome-panel), which is consequently always on top, and
add partial struts to allow xfwm to do the right thing.

Olivier, I noticed partial struts are only enforced on the screen top edge, is
this by design?


Please test this.

Flame away,

	Jasper