GConf Editor - Use Theme Icons

[Christopher Bratusek <nano-master gmx de>]

The patch is here for weeks now, but no response from the Devs, so I'm
trying here.

My patch for GConf-Editor to use Icons of the current Theme is available
here:

http://bugzilla.gnome.org/show_bug.cgi?id=348822#c37

Michael Monreal has made some new tangofied icons for the gconf-editor
[and the new mimetype icons, which are needed by my patch as fallback]

http://bugzilla.gnome.org/show_bug.cgi?id=348822#c30

At least a review would be nice.

Chris