Outline files not listed in the data dependencies for spine files

A minor inconsistency was found in the management of spine/outline data dependencies.

From the GUI, on editing a spine file and saving the editions into a label file, the data dependencies element lists the spine file only. Similarly, editing an outline file and saving to file generates a label file that lists both the outline file and the corresponding spine file the outline file only.

Recording both the spine and outline filesThe second behavior is expected in both cases.