Align with `sbmufl` changes

[ilizol]

• Add rclt for yporroi and gorgon
  • neanes/sbmufl@1323b25
• Position yporroi gorgon barlines via substitution anchors
  • Position yporroi gorgon barlines via substitution anchors neanes/sbmufl#48
• Add zero-space scripts
  • Add zero-space scripts neanes/sbmufl#49
• Add ascent and descent to the metadata
  • neanes/sbmufl@8236e23
• Add secondary neume to double apostrophos
  • neanes/sbmufl@46c9a61
• Add markAttachmentClasses
  • Add markAttachmentClasses neanes/sbmufl#62
• Add elafronBounds
  • Add elafronBounds neanes/sbmufl#63