* Makefile.am testOOM.c testOOMlib.[ch] : integrated the Out Of
  Memory test from Havoc Pennington #109368
* SAX.c parser.c parserInternals.c tree.c uri.c valid.c
  xmlmemory.c xmlreader.c xmlregexp.c include/libxml/tree.h
  include/libxml/parser.h: a lot of memory allocation cleanups
  based on the results of the OOM testing
* check-relaxng-test-suite2.py: seems I forgot to commit the
  script.
Daniel