Creates a new Validator that can be used to validate XML documents with
respect to this schema. The PropertyMap should contain a
ValidateProperty.ERROR_HANDLER property, which will be
used to report errors. If it does not, then an ErrorHandler
will be used that ignores warnings and throws its argument on errors and fatal errors.
Common properties are defined in ValidateProperty. Implementations
may support additional properties.
properties - a PropertyMap specifying the properties of the
Validator to be created
a new Validator that can be used to validate an XML document
with respect to this schema; never null