added entities testing to the Thread test make the test reasonable fix the

* test/threads/*: added entities testing to the Thread test
* testThreads.c: make the test reasonable
* DOCBparser.c: fix the DTD public and system ID
* xmllint.c: added --sgml for SGML DocBook importing
* Makefile.am: added Docbtests target
Daniel
diff --git a/testThreads.c b/testThreads.c
index 310a239..8424d31 100644
--- a/testThreads.c
+++ b/testThreads.c
@@ -90,7 +90,7 @@
     int ret;
 
     xmlInitParser();
-    for (repeat = 0;repeat < 10000;repeat++) {
+    for (repeat = 0;repeat < 500;repeat++) {
 	xmlLoadCatalog(catalog);
 
 	for (i = 0; i < num_threads; i++) {