security: renaming PolicyManager classess to SecPolicy___ and re-organize security file layout

Change-Id: Ibca0333129a3d4465ff294c4d97d59808ae253f4
diff --git a/src/node.cpp b/src/node.cpp
index 404853e..6641bbc 100644
--- a/src/node.cpp
+++ b/src/node.cpp
@@ -14,7 +14,7 @@
 
 #include "util/ndnd-id-fetcher.hpp"
 
-#include <ndn-cpp/security/signature/signature-sha256-with-rsa.hpp>
+#include <ndn-cpp/security/signature-sha256-with-rsa.hpp>
 #include <ndn-cpp/status-response.hpp>
 
 using namespace std;