allow to inherit attributes from the DTD directly in the tree, this is

* SAX.c testXPath.c valid.c xmllint.c include/libxml/valid.h:
  allow to inherit attributes from the DTD directly in the
  tree, this is needed for XPath and can be a useful feature.
  Inherited namespaces are always provided at the tree level now
* test/defattr* result/defattr* result/noent/defattr*: added a couple
  of tests for this feature (XSLT being the prime user).
Daniel
diff --git a/result/defattr.xml b/result/defattr.xml
new file mode 100644
index 0000000..0a4ac15
--- /dev/null
+++ b/result/defattr.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0"?>
+<!DOCTYPE doc [
+<!ELEMENT doc EMPTY>
+<!ATTLIST doc xmlns CDATA #FIXED "http://www.example.com/">
+]>
+<doc xmlns="http://www.example.com/"/>