Number types could be more precise

[JDziurlaj]

Organization Name: The Turnout

Organization Type: 1 (CTR)

Document: Various

A lot of properties in the CDF data models use xs:integer. However, this allows for negative numbers, which makes little sense in most cases. For example, negative BallotsCast or Round. The XDM supports several subtypes, including xs:nonNegativeInteger, and should be explored.