xmlStrstr args are both const small cleanup reformated, fixed problems if

* include/libxml/parser.h parser.c: xmlStrstr args are both const
* xpath.c: small cleanup
* xmlGetNsList: reformated, fixed problems if used on Entities
Daniel
diff --git a/include/libxml/parser.h b/include/libxml/parser.h
index 5ff8ab6..f3ae597 100644
--- a/include/libxml/parser.h
+++ b/include/libxml/parser.h
@@ -381,7 +381,7 @@
 const xmlChar *	xmlStrchr		(const xmlChar *str,
 					 xmlChar val);
 const xmlChar *	xmlStrstr		(const xmlChar *str,
-					 xmlChar *val);
+					 const xmlChar *val);
 const xmlChar *	xmlStrcasestr		(const xmlChar *str,
 					 xmlChar *val);
 int		xmlStrcmp		(const xmlChar *str1,