applied patch from Aleksey Sanin fixing a problem in the canonicalization

* c14n.c: applied patch from Aleksey Sanin fixing a problem in the
  canonicalization algorithm
* doc/xml.html doc/index.html: added the C14N references on the
  index page.
Daniel
diff --git a/doc/xmlio.html b/doc/xmlio.html
index e462338..afa9213 100644
--- a/doc/xmlio.html
+++ b/doc/xmlio.html
@@ -247,6 +247,7 @@
 
 
 
+
 } </pre>
 </li>
 <li>And then use it to save the document: