improving some documentation comments found and fixed a mem leak with

* tree.c: improving some documentation comments
* xmlregexp.c: found and fixed a mem leak with python regression tests
* doc/*: rebuilt the doc and the API XML file including the
  xmlregexp.h xmlautomata.h and xmlunicode.h headers
* python/generator.py python/libxml2class.txt python/libxml_wrap.h
  python/types.c: added access to the XML Schemas regexps from
  python
* python/tests/Makefile.am python/tests/regexp.py: added a
  simple regexp bindings test
Daniel
diff --git a/xmlregexp.c b/xmlregexp.c
index d6bcb77..627da51 100644
--- a/xmlregexp.c
+++ b/xmlregexp.c
@@ -3852,6 +3852,13 @@
 	return(comp->determinist);
 
     am = xmlNewAutomata();
+    if (am->states != NULL) {
+	int i;
+
+	for (i = 0;i < am->nbStates;i++)
+	    xmlRegFreeState(am->states[i]);
+	xmlFree(am->states);
+    }
     am->nbAtoms = comp->nbAtoms;
     am->atoms = comp->atoms;
     am->nbStates = comp->nbStates;