mapping Character and char

[Benson Margulies]

Mapping either of these to a restricted xsd:string runs them straight
into the 'valid XML 1.0 Unicode subset' issue. More fun yet, a Java
'character' will hold a non-BMP Unicode character, and those range
from 0 to 2**32-1, sort of. I think that mapping them to restrictions
on positive integers makes more sense.