OASIS RelaxNG testsuite python script to run regression against OASIS

* test/relaxng/OASIS/spectest.xml: OASIS RelaxNG testsuite
* check-relaxng-test-suite.py: python script to run regression
  against OASIS RelaxNG testsuite
* relaxng.c: some cleanup tweaks
* HTMLparser.c globals.c: cleanups in comments
* doc/libxml2-api.xml: updated the API
* result/relaxng/*: errors moved files, so large diffs but
  no changes at the semantic level.
Daniel
diff --git a/doc/libxml2-api.xml b/doc/libxml2-api.xml
index ad21fcd..828beb6 100644
--- a/doc/libxml2-api.xml
+++ b/doc/libxml2-api.xml
@@ -9437,7 +9437,7 @@
     </function>
     <function name='xmlXPathCompile' file='xpath'>
       <info>Compile an XPath expression</info>
-      <return type='xmlXPathCompExprPtr' info='the xmlXPathObjectPtr resulting from the evaluation or NULL. the caller has to free the object.'/>
+      <return type='xmlXPathCompExprPtr' info='the xmlXPathCompExprPtr resulting from the compilation or NULL. the caller has to free the object.'/>
       <arg name='str' type='const xmlChar *' info='the XPath expression'/>
     </function>
     <function name='xmlXPathCompiledEval' file='xpath'>