[ubuntu-art] Theme update: HeatedGraphite -> Silicon-0.2

[Mikkel Kamstrup Erlandsen]

I updated the HeatedGraphite theme.

First on foremost - I've changed the name to "Silicon". Then there are a
ton of minor tweaks, but let's not get lost in details - try it out!

Theme: http://www.skim.dk/Silicon/Silicon-0.2.tar.gz
Icons: http://www.skim.dk/HeatedGraphite/Tango-Aluminum.tar.gz
Wallpaper: http://www.skim.dk/Silicon/ubuntu-silicon.png [1]
Screenie: http://www.skim.dk/Silicon/Silicon.png

[1]: Save the wallpaper in /usr/share/wallpapers for the theme to pick
it up automagically [2].

[2]: Maybe the Human theme should use this trick too?

The wiki pages are of course updated accordingly. You'll (also) find
everything you need on https://wiki.ubuntu.com/ArtworkTeam/Silicon.

PLEASE TEST IT!

Cheers,
Mikkel