util: Porting NotificationSubscriber, FaceMonitor, and NotificationStream from NFD

New generic classes:
- `util::NotificationSubscriber` (`util/notification-subscriber.hpp`)
- `util::NotificationStream` (`util/notification-stream.hpp`)

NFD Face monitoring class:
- `nfd::FaceMonitor` (`management/nfd-face-monitor.hpp`)

Change-Id: I2ab0a2cd9d7e3ac07036f290f0b4de5eb16e6e38
diff --git a/tests/unit-tests/management/test-nfd-controller.cpp b/tests/unit-tests/management/test-nfd-controller.cpp
index 525d0d0..7132c69 100644
--- a/tests/unit-tests/management/test-nfd-controller.cpp
+++ b/tests/unit-tests/management/test-nfd-controller.cpp
@@ -22,7 +22,7 @@
 #include "management/nfd-controller.hpp"
 #include "management/nfd-control-response.hpp"
 
-#include "../transport/dummy-face.hpp"
+#include "../dummy-client-face.hpp"
 
 #include <boost/tuple/tuple.hpp>
 
@@ -30,6 +30,9 @@
 
 namespace ndn {
 namespace nfd {
+namespace tests {
+
+using namespace ::ndn::tests;
 
 BOOST_AUTO_TEST_SUITE(ManagementTestNfdController)
 
@@ -37,7 +40,7 @@
 {
 protected:
   CommandFixture()
-    : face(makeDummyFace())
+    : face(makeDummyClientFace())
     , controller(*face)
     , commandSucceedCallback(bind(&CommandFixture::onCommandSucceed, this, _1))
     , commandFailCallback(bind(&CommandFixture::onCommandFail, this, _1, _2))
@@ -58,7 +61,7 @@
   }
 
 protected:
-  shared_ptr<DummyFace> face;
+  shared_ptr<DummyClientFace> face;
   Controller controller;
   KeyChain keyChain;
 
@@ -188,5 +191,6 @@
 
 BOOST_AUTO_TEST_SUITE_END()
 
+} // namespace tests
 } // namespace nfd
 } // namespace ndn