script_utils.getObjects() sorts by IDs

See bug #10745. We now sort objects by IDs in script_utils.getObjects().

To test:

 - Select a bunch of images and open split view figure dialog in Web.
 - Re-order the images by dragging & dropping rows (handle to left of each row) 
 - Grab a screen-shot (makes comparing easier)
 - Run script and check that the figure generated has the same order of rows as the preview.