some cleanups extended the document to cover RelaxNG and tree operations

* relaxng.c: some cleanups
* doc/xmlreader.html: extended the document to cover RelaxNG and
  tree operations
* python/tests/Makefile.am python/tests/reader[46].py: added some
  xmlReader example/regression tests
* result/relaxng/tutor*.err: updated the output of a number of tests
Daniel
14 files changed