[Design-team] Supplemental Wallpapers Package

[Martin Sourada]

Hi all,

I've finaly found some time to work on the supplemental wallpapers
pacakge. Here's the result for early testing:
http://mso.fedorapeople.org/packages/F14/RPMS/

The git commit it's based on is here:
http://git.fedorahosted.org/git/?p=design-team.git;a=commit;h=d6bbd7a72f6e52aa98b68865eb5adcf597b6b0ce

What I'd like from you to review before I push it to fedora is:
1. The Attribution file. It gets installed with the -single package
which is required by both -gnome and -kde
2. The .desktop files -- there's some attribution as well, I might
have make an error here and there
3. The desktop-backgrounds-lauglin-extras.xml -- the attribution info
I tried to add does not show in background properties and I don't know
whether it's my fault or whether it isn't supported. Plus, again, I
might have made a mistake when filling it out.
4. Two images were left out from Marc's slideshow XML [1] -- Oh
Tomorrow I’m Alone and Thou Apocalypse by Hamed Saber so I left them
out as well. Was that because they're licensing wasn't verified yet?

Plus, I went ahead and sanitized the filenames a bit...

Thanks,
Martin

References:
[1] http://marcstewart.fedorapeople.org/f14/supplemental/F14_Supplemental.xml