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/libxml.py b/python/libxml.py
index 8e5ba2a..a1b5a7b 100644
--- a/python/libxml.py
+++ b/python/libxml.py
@@ -378,6 +378,7 @@
 PARSER_LOADDTD=1
 PARSER_DEFAULTATTRS=2
 PARSER_VALIDATE=3
+PARSER_SUBST_ENTITIES=4
 
 #
 # Everything below this point is automatically generated