enhanced for range checking, updated to Unicode version 4.0.1 (API docs

* genUnicode.py, xmlunicode.c, include/libxml/xmlunicode.h,
  python/libxml2class.txt: enhanced for range checking,
  updated to Unicode version 4.0.1 (API docs also updated)
* python/generator.py: minor change to fix a warning
8 files changed