src: Refactoring common.hpp and minimizing exposed includes

Face class has relatively large rewrite to hide internals using
Implementor pattern.  As of this commit, <boost/asio.hpp> is not
automatically included whenever ndn-cxx/face.hpp is included.  If it is
needed to directly work with io_service, asio.hpp should be specifically
included.

Change-Id: Ie742b851025b4e3da634eb981319df0f42937855
diff --git a/src/security/sec-public-info-memory.hpp b/src/security/sec-public-info-memory.hpp
index 0c6b70f..20ccde6 100644
--- a/src/security/sec-public-info-memory.hpp
+++ b/src/security/sec-public-info-memory.hpp
@@ -18,6 +18,8 @@
 #include "../common.hpp"
 #include "sec-public-info.hpp"
 
+#include <map>
+
 namespace ndn {
 
 /**