Prepare release 0.4

Change-Id: Id00ffc0edb4b3fa0bb4826f3e48af21e982955d4
diff --git a/wscript b/wscript
index 42cb690..00d472f 100644
--- a/wscript
+++ b/wscript
@@ -1,6 +1,6 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 
-VERSION = '0.3'
+VERSION = '0.4'
 APPNAME = 'ndn-tools'
 GIT_TAG_PREFIX = 'ndn-tools-'