Add IANA registered image/emf
Add IANA registered image/emf

Former image/x-emf is deprecated in favor of image/emf.

https://bugzilla.gnome.org/show_bug.cgi?id=782390

GNOME/gdk-pixbuf,GNOME/gdk-pixbuf,GNOME/gdk-pixbuf,GNOME/gdk-pixbuf