fixed URIRef including native unicode characters
fixed URIRef including native unicode characters

URIRef should be able to include native unicode like <http://ja.dbpedia.org/resource/日本> equal to <http://ja.dbpedia.org/resource/\\u65e5\\u672c>.
Adding the code as same as line 185-187.
RDFLib/rdflib,RDFLib/rdflib,RDFLib/rdflib,RDFLib/rdflib