added support for large file, tested with a 3+GB instance, and some

* libxml.h include/libxml/parser.h parser.c xmlIO.c DOCBparser.c:
  added support for large file, tested with a 3+GB instance,
  and some cleanup.
* catalog.c: added a TODO
* Makefile.am: added some "make tests" comments
Daniel
diff --git a/include/libxml/parser.h b/include/libxml/parser.h
index d221825..d623e73 100644
--- a/include/libxml/parser.h
+++ b/include/libxml/parser.h
@@ -55,7 +55,12 @@
     int length;                       /* length if known */
     int line;                         /* Current line */
     int col;                          /* Current column */
-    int consumed;                     /* How many xmlChars already consumed */
+    /*
+     * NOTE: consumed is only tested for equality in the parser code,
+     *       so even if there is an overflow this should not give troubles
+     *       for parsing very large instances.
+     */
+    unsigned long consumed;           /* How many xmlChars already consumed */
     xmlParserInputDeallocate free;    /* function to deallocate the base */
     const xmlChar *encoding;          /* the encoding string for entity */
     const xmlChar *version;           /* the version string for entity */