Ads ROI classes representing sets of vertebrae and vertebral elements.

[cuboideum]

This ads the following anatomical regions of interests:

• 'Entire set of all vertebrae' (rdfbones:EntireSetOfAllVertebrae)
• 'Entire set of all neural arches' (rdfbones:EntireSetOfAllNeuralArches)
• 'Entire set of all vertebral bodies' (rdfbones:EntireSetOfAllVertebralBodies)

Fixes #194.