fixed xmlReconciliateNs(), added a Python test/example for inter-document

* tree.c python/tests/Makefile.am python/tests/cutnpaste.py:
  fixed xmlReconciliateNs(), added a Python test/example for
  inter-document cut'n paste
* python/libxml.py: fixed node.doc on document nodes and added
  xpathEval() onto node objects
Daniel

python/tests/cutnpaste.py

@@ -0,0 +1,48 @@
+#!/usr/bin/python -u
+import sys
+import libxml2
+
+# Memory debug specific
+libxml2.debugMemory(1)
+
+#
+# Testing XML document serialization
+#
+source = libxml2.parseDoc("""<?xml version="1.0"?>
+<root xmlns:foo="http://example.org/foo"
+      xmlns:bar="http://example.org/bar">
+<include xmlns="http://example.org/include">
+<fragment><foo:elem bar="tricky"/></fragment>
+</include>
+</root>
+""")
+
+target = libxml2.parseDoc("""<?xml version="1.0"?>
+<root xmlns:foobar="http://example.org/bar"/>""")
+
+fragment = source.xpathEval("//*[name()='fragment']")[0]
+dest = target.getRootElement()
+
+# do a cut and paste operation
+fragment.unlinkNode()
+dest.addChild(fragment)
+# do the namespace fixup
+dest.reconciliateNs(target)
+
+# The source tree can be freed at that point
+source.freeDoc()
+
+# check the resulting tree
+str = dest.serialize()
+if str != """<root xmlns:foobar="http://example.org/bar" xmlns:default="http://example.org/include" xmlns:foo="http://example.org/foo"><default:fragment><foo:elem bar="tricky"/></default:fragment></root>""":
+    print "reconciliateNs() failed"
+    sys.exit(1)
+target.freeDoc()
+
+# Memory debug specific
+libxml2.cleanupParser()
+if libxml2.debugMemory(1) == 0:
+    print "OK"
+else:
+    print "Memory leak %d bytes" % (libxml2.debugMemory(1))
+    libxml2.dumpMemory()