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
diff --git a/HTMLparser.c b/HTMLparser.c
index 2907065..138bf73 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -5493,7 +5493,7 @@
   return ( elt->dtd == 0 ) ? HTML_VALID : HTML_DEPRECATED ;
 }
 /**
- * htmlAttrAllowed
+ * htmlAttrAllowed:
  * @elt: HTML element
  * @attr: HTML attribute
  * @legacy: whether to allow deprecated attributes
@@ -5528,7 +5528,7 @@
   return HTML_INVALID ;
 }
 /**
- * htmlNodeStatus
+ * htmlNodeStatus:
  * @node - an htmlNodePtr in a tree
  * @legacy - whether to allow deprecated elements (YES is faster here
  *	for Element nodes)