implemented patches supplied by Olivier Andrieu (bug 148588), plus made

* SAX2.c, error.c, parser.c, tree.c, xmlreader.c:
  implemented patches supplied by Olivier Andrieu
  (bug 148588), plus made some further enhancements, to
  correct some problems with out of memory conditions.
* testOOM.c: improved with patches from Olivier Andrieu
7 files changed