Remove pixmap from Image, as there are no pixmaps on GTK3 anymore:
https://developer.gnome.org/gtk3/stable/ch26s02.html#id-1.6.3.4.5

Also remove printWindow() functionality, as it will never work on GTK3
because it uses GdkDrawable. It will need to be re-implemented.

Change-Id: I7d1dd7d9cb7ce52cdf27fe707d45cca0f477f562
Signed-off-by: Eric Williams <ericwill@redhat.com>