Add Preferences to Scan Options.
All changes are made according to design, taken from: https://raw.githubusercontent.com/gnome-design-team/gnome-mockups/master/document-scanner/document-scanner.png
Edited by Bartosz
All changes are made according to design, taken from: https://raw.githubusercontent.com/gnome-design-team/gnome-mockups/master/document-scanner/document-scanner.png