implemented the XML_PARSE_NONET parser option. converted xmllint.c to use

* parser.c xmlIO.c include/libxml/parserInternals.h: implemented
  the XML_PARSE_NONET parser option.
* xmllint.c: converted xmllint.c to use the option instead of
  relying on the global resolver variable.
Daniel
diff --git a/xmlIO.c b/xmlIO.c
index 33c544b..02c5ec9 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -3091,6 +3091,15 @@
                     "xmlDefaultExternalEntityLoader(%s, xxx)\n", URL);
 #endif
 #ifdef LIBXML_CATALOG_ENABLED
+    if ((ctxt != NULL) && (ctxt->options & XML_PARSE_NONET)) {
+        int options = ctxt->options;
+
+	ctxt->options -= XML_PARSE_NONET;
+        ret = xmlNoNetExternalEntityLoader(URL, ID, ctxt);
+	ctxt->options = options;
+	return(ret);
+    }
+
     /*
      * If the resource doesn't exists as a file,
      * try to load it from the resource pointed in the catalogs