* xmlschemas.c: Added output of canonical values in
  identity-constraint error messages.
* xmlschemastypes.c include/libxml/xmlschemastypes.h:
  Added xmlSchemaGetCanonValueWhtsp() to the API.
  Further enhancement of the canonical value
  conversion.
* test/schemas/changelog093_0.*: Added test with an XSD
  submitted by Randy J. Ray.