gnome-control-center freeze break request

[Marek Kasik <mkasik redhat com>]

Bug 683229 - implement new design for 'add printer' dialog
 - https://bugzilla.gnome.org/show_bug.cgi?id=683229

I want to commit new design of new printer dialog in
gnome-control-center's Printers panel.

The design is a simplification of current dialog so it is well-arranged.
It also uses asynchronous methods instead of synchronous ones so it is
more responsive.

I've put quite a lot of testing into it over past weeks.

We've agreed with Bastien that I can commit the change (I will just
split those patches a little bit more yet to have particular changes
well separated).

Regards

Marek