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/table/pit.cpp b/daemon/table/pit.cpp
index 7742266..168a64e 100644
--- a/daemon/table/pit.cpp
+++ b/daemon/table/pit.cpp
@@ -7,7 +7,7 @@
 #include "pit.hpp"
 #include <algorithm>
 
-namespace ndn {
+namespace nfd {
 
 Pit::Pit()
 {
@@ -73,4 +73,4 @@
   m_table.remove(pitEntry);
 }
 
-} // namespace ndn
+} // namespace nfd