fixed bug with plain literal representation of xsd.decimals
fixed bug with plain literal representation of xsd.decimals

ssssam/rdflib,dbs/rdflib,RDFLib/rdflib,ssssam/rdflib,ssssam/rdflib,avorio/rdflib,marma/rdflib,avorio/rdflib,armandobs14/rdflib,dbs/rdflib,ssssam/rdflib,armandobs14/rdflib,yingerj/rdflib,dbs/rdflib,dbs/rdflib,RDFLib/rdflib,yingerj/rdflib,avorio/rdflib,RDFLib/rdflib,marma/rdflib,RDFLib/rdflib,yingerj/rdflib,marma/rdflib,avorio/rdflib,armandobs14/rdflib,marma/rdflib,yingerj/rdflib,armandobs14/rdflib