PyNDN: Initial changes of PyNDN emulation in ndnSIM

The biggest problem so far, which I cannot solve at all, is exception
handling.  NDN.cxx throws many exceptions when something bad happens,
with are not handled by python bindings

Refs #1008 (http://redmine.named-data.net/issues/1008)
Refs #1011 (http://redmine.named-data.net/issues/1011)
diff --git a/wscript b/wscript
index f192ace..b48adf7 100644
--- a/wscript
+++ b/wscript
@@ -191,7 +191,7 @@
 
     bld.recurse ('tools')
 
-    # bld.ns3_python_bindings()
+    bld.ns3_python_bindings()
 
 
 @TaskGen.feature('ns3fullmoduleheaders')