plugins/ip-faces: ip-faces plugin, which implements ndn::TcpFace

This commit also includes a basic example showing how to work with
TcpFace.  The code compiles and passes basic tests, but requires more
work and proper documentation

Refs #1006 (http://redmine.named-data.net/)
diff --git a/examples/wscript b/examples/wscript
index 49a0c5c..c5c35eb 100644
--- a/examples/wscript
+++ b/examples/wscript
@@ -94,3 +94,7 @@
 
     obj = bld.create_ns3_program('ndn-simple-with-link-failure', all_modules)
     obj.source = 'ndn-simple-with-link-failure.cc'
+
+    if 'ip-faces' in bld.env['NDN_plugins']:
+        obj = bld.create_ns3_program('ndn-simple-tcp', all_modules)
+        obj.source = 'ndn-simple-tcp.cc'