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/fib.cpp b/daemon/table/fib.cpp
index 1d8fe3a..532ad97 100644
--- a/daemon/table/fib.cpp
+++ b/daemon/table/fib.cpp
@@ -8,7 +8,7 @@
 #include <algorithm>
 #include <numeric>
 
-namespace ndn {
+namespace nfd {
 
 Fib::Fib()
 {
@@ -75,4 +75,4 @@
 }
 
 
-} // namespace ndn
+} // namespace nfd