Several fixes for annotate-spacing.

Several fixes for annotate-spacing.

- Fixes annotate-spacing to use the new spacing names.
- Annotates spacing between staves as well as spacing between systems.
- Fixes some collisions between annotations.
- Padding (between systems, titles and staves) is properly annotated,
  with the annotation occuring at the horizontal position where the
  collision would actually happen. If the padding is the cause of the
  vertical spacing, it is highlighted in green.