all: cleanup common.hpp and import typenames from ndn namespace.

This allows us to compile NFD in C++11 mode, making use of std::shared_ptr,
std::function, std::bind, etc. rather than their boost equivalents
(provided that ndn-cpp-dev is also compiled in C++11 mode). This is an
experimental feature and may not work properly.

Change-Id: I310529f78e1e428a8530b087983130d1ef3a9d88
diff --git a/daemon/mgmt/command-validator.cpp b/daemon/mgmt/command-validator.cpp
index 22b8257..ac08228 100644
--- a/daemon/mgmt/command-validator.cpp
+++ b/daemon/mgmt/command-validator.cpp
@@ -29,6 +29,7 @@
 #include <ndn-cpp-dev/security/identity-certificate.hpp>
 
 #include <boost/filesystem.hpp>
+#include <fstream>
 
 namespace nfd {