[ndnSIM] Adding signals in the base Link Service

Change-Id: I6c20fe17cf41a7437579d8b5a5a9b8d51293a85a
diff --git a/daemon/face/link-service.cpp b/daemon/face/link-service.cpp
index 9b05c2a..363580c 100644
--- a/daemon/face/link-service.cpp
+++ b/daemon/face/link-service.cpp
@@ -60,6 +60,8 @@
   ++this->nOutInterests;
 
   doSendInterest(interest);
+
+  afterSendInterest(interest);
 }
 
 void
@@ -71,6 +73,8 @@
   ++this->nOutData;
 
   doSendData(data);
+
+  afterSendData(data);
 }
 
 void
@@ -82,6 +86,8 @@
   ++this->nOutNacks;
 
   doSendNack(nack);
+
+  afterSendNack(nack);
 }
 
 void