model: First set of major API changes and reorganizations

Main motive: change interface in Face class, resulting in need to change forwarding strategy interfaces

Refs #1005 (http://redmine.named-data.net/)
diff --git a/apps/ndn-app.cc b/apps/ndn-app.cc
index d29f509..7880849 100644
--- a/apps/ndn-app.cc
+++ b/apps/ndn-app.cc
@@ -64,8 +64,7 @@
 }
     
 App::App ()
-  : m_protocolHandler (0)
-  , m_active (false)
+  : m_active (false)
   , m_face (0)
 {
 }
@@ -85,12 +84,6 @@
   Application::DoDispose ();
 }
 
-void
-App::RegisterProtocolHandler (ProtocolHandler handler)
-{
-  m_protocolHandler = handler;
-}
-
 uint32_t
 App::GetId () const
 {
@@ -164,7 +157,7 @@
   // step 3. Destroy face
   if (m_face->GetReferenceCount () != 1)
     {
-      NS_LOG_ERROR ("Please a bug report on https://github.com/NDN-Routing/ndnSIM/issues:");
+      NS_LOG_ERROR ("Please a bug report on https://github.com/NDN-Routing/ndnSIM/issues");
       NS_LOG_ERROR ("At this point, nobody else should have referenced this face, but we have "
                     << m_face->GetReferenceCount () << " references");