* [RDF_REIFICATION_READ,RDF_REIFICATION_WRITE,RDF_REIFICATION_PRINT,SC]
  Split RDF reification module into three parts.
  Added and corrected documentation.
* [RDF_REIFICATION_READ,NEW] Added rdf_datatype_statement/6.
* [RDF_REIFICATION_WRITE,NEW] Added rdf_assert_datatype_statement/6.
* [RDF_REIFICATION_WRITE,FIX] Predicate export fix.