[themes] Tango iconset: Default for drupal, is NOT GPL.

[Bèr Kessels]

Hello,

I only realised this today, but our guidelines speak about using tango as 
default iconset. We abide these rules very well, in the contribs the mayority 
if icons are indeed tango icons.

But they are not GPL, nor can they be distributed as such. We should address 
this, and possibly choose another default iconset, or else change our 
licencing policy.

«The Tango icons are licensed under the Creative Commons Attribution 
Share-Alike license. The palette is public domain, it can be used and 
distributed freely. Developers, feel free to ship it along with your 
application. The icon naming utilities are licensed under the GPL»
        --- from http://tango-project.org/Tango_Desktop_Project

Bèr