3D View: add object color drawing option

Has some advantages over existing options.

- Using material links color to rendering with no way to vary colors
  if objects share a material.
- Random gives no control, objects may randomly have the same color,
  duplicating an object often changes it's color.

release/scripts/startup/bl_ui/space_view3d.py

@@ -4378,7 +4378,7 @@ class VIEW3D_PT_shading(Panel):
     bl_space_type = 'VIEW_3D'
     bl_region_type = 'HEADER'
     bl_label = "Shading"
-    bl_ui_units_x = 11
+    bl_ui_units_x = 12
 
     @classmethod
     def get_shading(cls, context):