extended the XmlTextReader API a bit, addding accessors for the current

* xmlreader.c include/libxml/xmlreader.h doc/libxml2-api.xml:
  extended the XmlTextReader API a bit, addding accessors for
  the current doc and node, and an entity substitution mode for
  the parser.
* python/libxml.py python/libxml2class.txt: related updates
* python/tests/Makefile.am python/tests/reader.py
  python/tests/reader2.py python/tests/reader3.py: updated a bit
  the old tests and added a new one to test the entities handling
Daniel
diff --git a/python/libxml2class.txt b/python/libxml2class.txt
index 93c2e9d..2fbc707 100644
--- a/python/libxml2class.txt
+++ b/python/libxml2class.txt
@@ -565,6 +565,8 @@
     AttributeCount()
     BaseUri()
     Close()
+    CurrentDoc()
+    CurrentNode()
     Depth()
     GetAttribute()
     GetAttributeNo()