src: Changing namespace ndn to namespace nfd

Also, this commit imports used classes from ::ndn namespace (from
NDN-CPP library) directly to ::nfd namespace.

refs: #1163

Change-Id: I9cc9d72e00af495b4ed0c84e6d418a7c9ba986cb
diff --git a/daemon/core/scheduler.hpp b/daemon/core/scheduler.hpp
index d5d57aa..4b2e2d4 100644
--- a/daemon/core/scheduler.hpp
+++ b/daemon/core/scheduler.hpp
@@ -10,7 +10,7 @@
 #include "common.hpp"
 #include "monotonic_deadline_timer.hpp"
 
-namespace ndn {
+namespace nfd {
 
 struct EventIdImpl; ///< \brief Private storage of information about the event
 /**
@@ -94,6 +94,6 @@
   boost::asio::monotonic_deadline_timer m_deadlineTimer;
 };
 
-} // namespace ndn
+} // namespace nfd
 
 #endif // NFD_CORE_SCHEDULER_HPP