Binding Model API: restrictions do not match java type

Restrictions returned for a particular ConcreteType should match the underlying type. The parser generates restrictions in whatever the default is, for example 0 for Short is expressed as a Long. This is largely fine in binding-independent world, but makes it unusable if we want to actually use restrictions with objects of that type.

BaseYangTypes is a prime offender, as its singleRangeRestrictions() callers do the wrong thing. Furthermore BindingGeneratorUtil needs to translate whatever it sees to the appropriate type.