ACTION-5: Draft a presentation conversion for numbers

Is this still relevant?

I believe it has stayed opened until the cn contribution came in.

Since the notation-markup will, anyways, be concentrated in the CD-specification format, I suppose we can safely skip that part and let it be solved by a (future) note which would cover a more complete range of notation specification, leaving it to the renderers engineers to find out the way to note numbers as was done thus far.