comments cleanups use xmllint for doing the RelaxNG tests preparing 2.5.2

* HTMLparser.c tree.c xmlIO.c: comments cleanups
* Makefile.am: use xmllint for doing the RelaxNG tests
* configure.in: preparing 2.5.2 made schemas support default to
  on instead of off
* relaxng.c: removed the verbosity
* xmllint.c: added --relaxng option
* python/generator.py python/libxml_wrap.h: prepared the integration
  of the new RelaxNG module and schemas
* result/relaxng/*: less verbose output
Daniel
153 files changed