[Deskbar] Firefox 2.0 search engine support

["Mikkel Kamstrup Erlandsen" <mikkel kamstrup gmail com>]

I just checked in support for Firefox 2.0 search engines in the mozilla.py handler.

Can you guys please test this for the various Firefox releases you have around? 1.0, 1.5, 2.0...

It shouldn't break anything for older Foxes, but I honestly haven't tested it yet :-)

Cheers,
Mikkel

PS: I also added a bonus feature to the Match class. You can now pass a "pixbuf" containing a gtk.gdk.Pixbuf parameter directly to the constructor. I needed this since because the search engine files contains inlined bsase64 encoded images - thus I couldn't refer to a file as we usually do.