Luca Bacci authored Mar 27, 2019 and Mike Fleetwood committed Apr 06, 2019

Some icon themes only provide large icons for stock items.  This can
cause problems like overly large icons appearing in the GParted UI.
Found on Kubuntu 16.04 LTS with default breeze icon theme.

Be compatible with these icon themes by forcing scaling of stock icons
to the requested size.

Icons are used either by Gtk::Image widgets, or Gtk::CellRendererPixbuf
objects for comboboxes/treeviews.  For Gtk::Image widgets we add
Utils::mk_image() that constructs Gtk::Image widgets and then sets the
pixel-size property.  For Gtk::CellRendererPixbuf we add
Utils::mk_pixbuf() that first loads a Gdk::Pixbuf and then scales if
needed.

Closes #39 - After GTK3 port icons are too big on KDE