Bunch of fixes, finishing moving datastructures to the hash stuff:

- hash.[ch] debugXML.c: expanded/enhanced the API, added
  multikey tuples, made hash structure opaque
- valid.[ch]: moved elements, attributes, notations decalarations
  as well as ID and refs to hash tables.
- entities.c: hash cleanup
- xmlmemory.c: fixed a dump problem in debug mode
- include/Makefile.am: problem passing in DESTDIR= values patch
  from Marc Christensen <marc@calderasystems.com>
- nanohttp.c: removed debugging remains
- HTMLparser.c: the bogus tag should be ignored (Wayne)
- HTMLparser.c parser.c: fixing a number of problems with the
  macros in the *parser.c files (Wayne).
- HTMLparser.c: close the previous option when opening a new one
  (Marc Sanfacon).
- result/HTML/*: updated the HTML results accordingly
Daniel

xmlmemory.c

@@ -384,6 +384,11 @@ xmlMemContentShow(FILE *fp, MEMHDR *p)
     int i,j,len = p->mh_size;
     const char *buf = (const char *) HDR_2_CLIENT(p);
 
+    if (p == NULL) {
+	fprintf(fp, " NULL");
+	return;
+    }
+
     for (i = 0;i < len;i++) {
         if (buf[i] == 0) break;
 	if (!isprint(buf[i])) break;
@@ -401,7 +406,7 @@ xmlMemContentShow(FILE *fp, MEMHDR *p)
 		    if (p == q) break;
 		    p = p->mh_next;
 		}
-		if (p == q) {
+		if ((p != NULL) && (p == q)) {
 		    fprintf(fp, " pointer to #%lu at index %d",
 		            p->mh_number, j);
 		    return;