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/PyNDN/Interest.py b/PyNDN/Interest.py
index 7ebee01..3256a7c 100644
--- a/PyNDN/Interest.py
+++ b/PyNDN/Interest.py
@@ -33,7 +33,7 @@
 CHILD_SELECTOR_LEFT = 0
 CHILD_SELECTOR_RIGHT = 1
 
-class Interest(object):
+class Interest (object):
     def __init__(self, name = None, minSuffixComponents = None,
              maxSuffixComponents = None, publisherPublicKeyDigest = None,
              exclude = None, childSelector = None, answerOriginKind = None,