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

entities.c

@@ -153,6 +153,7 @@ xmlAddEntity(xmlDtdPtr dtd, const xmlChar *name, int type,
 	 * entity was already defined at another level.
 	 */
         xmlFreeEntity(ret);
+	return(NULL);
     }
     return(ret);
 }