more accessor classes for the parser context, allow to switch on and check

* python/TODO python/generator.py python/libxml2-python-api.xml
  python/libxml2class.txt: more accessor classes for the parser
  context, allow to switch on and check validity
* python/tests/Makefile.am python/tests/error.py
  python/tests/invalid.xml python/tests/valid.xml
  python/tests/validate.py: attded more test and and added error.py
  which I forgot to commit in the last step
Daniel

python/tests/validate.py

@@ -0,0 +1,72 @@
+#!/usr/bin/python -u
+import sys
+import libxml2
+
+ctxt = libxml2.createFileParserCtxt("valid.xml")
+ctxt.validate(1)
+ctxt.parseDocument()
+doc = ctxt.doc()
+valid = ctxt.isValid()
+
+if doc.name != "valid.xml":
+    print "doc.name failed"
+    sys.exit(1)
+root = doc.children
+if root.name != "doc":
+    print "root.name failed"
+    sys.exit(1)
+if valid != 1:
+    print "validity chec failed"
+    sys.exit(1)
+doc.freeDoc()
+
+i = 1000
+while i > 0:
+    ctxt = libxml2.createFileParserCtxt("valid.xml")
+    ctxt.validate(1)
+    ctxt.parseDocument()
+    doc = ctxt.doc()
+    valid = ctxt.isValid()
+    doc.freeDoc()
+    if valid != 1:
+	print "validity check failed"
+	sys.exit(1)
+    i = i - 1
+
+#desactivate error messages from the validation
+def noerr(ctx, str):
+    pass
+
+libxml2.registerErrorHandler(noerr, None)
+
+ctxt = libxml2.createFileParserCtxt("invalid.xml")
+ctxt.validate(1)
+ctxt.parseDocument()
+doc = ctxt.doc()
+valid = ctxt.isValid()
+if doc.name != "invalid.xml":
+    print "doc.name failed"
+    sys.exit(1)
+root = doc.children
+if root.name != "doc":
+    print "root.name failed"
+    sys.exit(1)
+if valid != 0:
+    print "validity chec failed"
+    sys.exit(1)
+doc.freeDoc()
+
+i = 1000
+while i > 0:
+    ctxt = libxml2.createFileParserCtxt("invalid.xml")
+    ctxt.validate(1)
+    ctxt.parseDocument()
+    doc = ctxt.doc()
+    valid = ctxt.isValid()
+    doc.freeDoc()
+    if valid != 0:
+	print "validity check failed"
+	sys.exit(1)
+    i = i - 1
+
+print "OK"