GEP 7 - icons and thumbnails

I have put gep nr 7 in the gep cvs module. It concerns moving the new 
nautilus icon + thumbnailing code to a common library.

Discussions about this gep should take place on 
[email protected], and in fact the discussion was already taking 
place like normal before I wrote this silly gep.

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 Alexander Larsson                                            Red Hat, Inc 
                   [email protected]    [email protected] 
He's an immortal vegetarian jungle king searching for his wife's true killer. 
She's a scantily clad streetsmart opera singer with her own daytime radio talk 
show. They fight crime!