Reworked the section on 'horizontals'

Deborah, Tzviya,

as agreed yesterday, I reworked the section on horizontals; here it is:

http://w3c.github.io/dpub-pwp-ucr/#the-publication-should-conform-to-all-the-requirements-of-horizontal-dependencies

Salt-'n-pepper at your will:-) But I hope this is the direction you had in mind!

(Needless to say, there are some cut-and-paste here from some W3C pages…)

Ivan


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Ivan Herman, W3C
Digital Publishing Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
ORCID ID: http://orcid.org/0000-0003-0782-2704