Make the dialog bigger (600x400). Add padding between list of manufacturers
and the list of drivers. Add padding to manufacturers and drivers lists.
Change Manufacturers and Drivers to singular. Trigger resizing of treeview
when list has changed so it has optimal width.
https://bugzilla.gnome.org/show_bug.cgi?id=690448
This commit adds popup window which when activated allows
user to select PPD from local database of installed PPDs,
select directly PPD from filesystem or select one from 3
recommended PPDs (#678637).
The popup is activated by clicking on model field (the panel
has to be unlocked). It starts to search for the best PPDs
available immediately after its popup.
All operations are asynchronous.
