patch from Sean Treadway, adding Python bindings for extension element and

* python/generator.py python/libxslt-python-api.xml python/libxslt.c
  python/libxslt_wrap.h python/libxsltclass.txt: patch from
  Sean Treadway, adding Python bindings for extension element and
  some bindings cleanups.
* python/tests/Makefile.am python/tests/extelem.py: also add an
  example/test.
Daniel

python/tests/extelem.py

@@ -0,0 +1,89 @@
+#!/usr/bin/python -u
+import sys
+import string
+import StringIO
+import libxml2
+# Memory debug specific
+libxml2.debugMemory(1)
+import libxslt
+
+EXT_URL="http://example.com/foo"
+
+insertNodeName = None
+transformNodeName = None
+
+def compile_test(style, inst, func):
+    pass
+
+def transform_test(ctx, node, inst, comp):
+    global insertNodeName
+
+    #
+    # Small check to verify the context is correcly accessed
+    #
+    try:
+        #
+        # FIXME add some more sanity checks
+        #
+        tctxt = libxslt.transformCtxt(_obj=ctx)
+        insertNodeName = tctxt.insertNode().name
+
+        # FIXME find and confirm the note being replaced is called 'test'
+        # transformNodeName = libxml2.xmlNode(inst).name
+    except:
+        pass
+
+    tctxt.insertNode().addContent('SUCCESS')
+    
+
+
+styledoc = libxml2.parseDoc("""
+<xsl:stylesheet version='1.0'
+  xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
+  xmlns:foo='%s'
+  xsl:extension-element-prefixes='foo'>
+
+  <xsl:template match='/'>
+    <article><foo:test>FAILURE</foo:test></article>
+    <deeper><article><foo:test>something<foo:test>nested</foo:test>even</foo:test></article></deeper>
+  </xsl:template>
+</xsl:stylesheet>
+""" % EXT_URL)
+
+style = libxslt.parseStylesheetDoc(styledoc)
+libxslt.registerExtModuleElement("test", EXT_URL, compile_test, transform_test)
+doc = libxml2.parseDoc("<doc/>")
+result = style.applyStylesheet(doc, None)
+style.freeStylesheet()
+doc.freeDoc()
+
+
+extensions = StringIO.StringIO()
+libxslt.debugDumpExtensions(extensions)
+
+if 0 and extensions.buf.find(EXT_URL) < 0:
+    print "Element extension not registered (or dumping broken)"
+    sys.exit(1)
+
+root = result.children
+
+if root.name != "article":
+    print "Unexpected root node name"
+    sys.exit(1)
+if root.content != "SUCCESS":
+    print "Unexpected root node content, extension function failed"
+    sys.exit(1)
+if insertNodeName != 'article':
+    print "The function callback failed to access its context"
+    sys.exit(1)
+
+result.dump(sys.stdout)
+result.freeDoc()
+
+# Memory debug specific
+libxslt.cleanup()
+if libxml2.debugMemory(1) == 0:
+    print "OK"
+else:
+    print "Memory leak %d bytes" % (libxml2.debugMemory(1))
+    libxml2.dumpMemory()