model+ndn.cxx+test: Finishing implementation of ApiFace (now timeouts are working as well)

Also, adding a basic test case to test ApiFace

Refs #1005 (http://redmine.named-data.net/)
diff --git a/examples/custom-apps/ndn-api-app.cc b/examples/custom-apps/ndn-api-app.cc
index 886a0b8..3346b52 100644
--- a/examples/custom-apps/ndn-api-app.cc
+++ b/examples/custom-apps/ndn-api-app.cc
@@ -77,7 +77,7 @@
 void
 ApiApp::StartApplication ()
 {
-  m_face = Create<ApiFace> (GetNode ());
+  m_face = CreateObject<ApiFace> (GetNode ());
   
   Simulator::Schedule (Seconds (1), &::ns3::ndn::ApiApp::RequestData, this);
 }
@@ -85,6 +85,9 @@
 void
 ApiApp::StopApplication ()
 {
+  NS_LOG_FUNCTION (this);
+  m_face->Shutdown ();
+  m_face = 0;
 }
 
 } // namespace ndn