3D View: add Backface Culling option, to hide faces when seen from the back side,

found in the Display panel.

Patch by Simon Kirk and Irie Shinsuke, refactored to also work for non-mesh objects
and avoid globals.

release/scripts/startup/bl_ui/space_view3d.py

@@ -2391,6 +2391,8 @@ class VIEW3D_PT_view3d_display(Panel):
             col.prop(gs, "material_mode", text="")
             col.prop(view, "show_textured_solid")
 
+        col.prop(view, "show_backface_culling")            
+
         layout.separator()
 
         region = view.region_quadview