removing xmldwalk module since it got merged with the xmlreader. cleanup

* Makefile.am configure.in xmldwalk.c xmlreader.c
  include/libxml/Makefile.am include/libxml/xmldwalk.h
  include/libxml/xmlversion.h.in: removing xmldwalk module
  since it got merged with the xmlreader.
* parser.c: cleanup
* win32/libxml2.def.src python/libxml2class.txt doc/libxml2-api.xml:
  rebuilt the API
* python/tests/Makefile.am python/tests/reader7.py
  python/tests/walker.py: adding regression testing for the
  new xmlreader APIs, new APIs for reader creation, including
  makeing reader "walker" operating on preparsed document trees.
Daniel

python/tests/reader7.py

@@ -0,0 +1,102 @@
+#!/usr/bin/python -u
+#
+# this tests the entities substitutions with the XmlTextReader interface
+#
+import sys
+import StringIO
+import libxml2
+
+# Memory debug specific
+libxml2.debugMemory(1)
+
+result = ""
+def processNode(reader):
+    global result
+
+    result = result + "%d %d %s %d\n" % (reader.Depth(), reader.NodeType(),
+			   reader.Name(), reader.IsEmptyElement())
+
+#
+# Parse a document testing the readerForxxx API
+#
+docstr="""<foo>
+<label>some text</label>
+<item>100</item>
+</foo>"""
+expect="""0 1 foo 0
+1 14 #text 0
+1 1 label 0
+2 3 #text 0
+1 15 label 0
+1 14 #text 0
+1 1 item 0
+2 3 #text 0
+1 15 item 0
+1 14 #text 0
+0 15 foo 0
+"""
+result = ""
+
+reader = libxml2.readerForDoc(docstr, "test1", None, 0)
+ret = reader.Read()
+while ret == 1:
+    processNode(reader)
+    ret = reader.Read()
+
+if ret != 0:
+    print "Error parsing the document test1"
+    sys.exit(1)
+
+if result != expect:
+    print "Unexpected result for test1"
+    print result
+    sys.exit(1)
+
+#
+# Reuse the reader for another document testing the ReaderNewxxx API
+#
+docstr="""<foo>
+<label>some text</label>
+<item>1000</item>
+</foo>"""
+expect="""0 1 foo 0
+1 14 #text 0
+1 1 label 0
+2 3 #text 0
+1 15 label 0
+1 14 #text 0
+1 1 item 0
+2 3 #text 0
+1 15 item 0
+1 14 #text 0
+0 15 foo 0
+"""
+result = ""
+
+reader.NewDoc(docstr, "test2", None, 0)
+ret = reader.Read()
+while ret == 1:
+    processNode(reader)
+    ret = reader.Read()
+
+if ret != 0:
+    print "Error parsing the document test2"
+    sys.exit(1)
+
+if result != expect:
+    print "Unexpected result for test2"
+    print result
+    sys.exit(1)
+
+#
+# cleanup
+#
+del reader
+
+# Memory debug specific
+libxml2.cleanupParser()
+if libxml2.debugMemory(1) == 0:
+    print "OK"
+else:
+    print "Memory leak %d bytes" % (libxml2.debugMemory(1))
+    libxml2.dumpMemory()