added xsd:include support, fixed testSchemas behaviour when a schemas

* include/libxml/schemasInternals.h include/libxml/xmlerror.h
  testSchemas.c xmlschemas.c: added xsd:include support, fixed
  testSchemas behaviour when a schemas failed to parse.
* test/schemas/vdv-* result/schemas/vdv-first5_0_0*: added one
  test for xsd:include from Eric Van der Vlist
Daniel
diff --git a/testSchemas.c b/testSchemas.c
index 2702518..de12e25 100644
--- a/testSchemas.c
+++ b/testSchemas.c
@@ -120,6 +120,8 @@
 		    xmlSchemaDump(stdout, schema);
 #endif
 #endif /* LIBXML_OUTPUT_ENABLED */
+		if (schema == NULL)
+		    goto failed_schemas;
 	    } else {
 		xmlDocPtr doc;
 
@@ -166,6 +168,7 @@
 	printf("\t--memory : test the schemas in memory parsing\n");
 #endif
     }
+failed_schemas:
     xmlSchemaCleanupTypes();
     xmlCleanupParser();
     xmlMemoryDump();