applied an old patch from Lukas Schroeder to track node creation and

* global.data globals.c tree.c include/libxml/globals.h: applied
  an old patch from Lukas Schroeder to track node creation and
  destruction. Probably missing a lot of references at the moment
  and not usable reliably.
Daniel
diff --git a/global.data b/global.data
index 43d2fb5..6b170dd 100644
--- a/global.data
+++ b/global.data
@@ -20,3 +20,5 @@
 #const xmlChar,xmlStringText,[]
 #const xmlChar,xmlStringTextNoenc,[]
 int,xmlSubstituteEntitiesDefaultValue
+xmlRegisterNodeFunc,xmlRegisterNodeDefaultValue
+xmlDeregisterNodeFunc,xmlDeregisterNodeDefaultValue