RMLSTC0003: fix relative path and SPARQL query

Contributes to #47

test-cases/RMLSTC0003/mapping.ttl

@@ -4,25 +4,23 @@
 @prefix formats: <https://www.w3.org/ns/formats/> .
 @base <http://example.com/rules/> .
 
-<#VoIDSourceAccess> a rml:Source, void:Dataset;
-  void:dataDump <file://./Friends.nt>;
-.
-
 <#TriplesMap> a rml:TriplesMap;
   rml:logicalSource [ a rml:LogicalSource;
-    rml:source <#VoIDSourceAccess>;
+    rml:source [ a rml:RelativePathSource;
+        rml:path "./Friends.nt";
+    ];
     rml:iterator """
     PREFIX foaf: <http://xmlns.com/foaf/0.1/>
 
-    SELECT ?name ?age WHERE {
+    SELECT ?person ?name ?age WHERE {
         ?person foaf:name ?name .
         ?person foaf:age ?age .
     }
     """;
     rml:referenceFormulation formats:SPARQL_Results_CSV;
   ];
   rml:subjectMap [ a rml:SubjectMap;
-    rml:template "http://example.org/{id}";
+    rml:reference "person";
   ];
   rml:predicateObjectMap [ a rml:PredicateObjectMap;
     rml:predicateMap [ a rml:PredicateMap;