encoding: Move oid support from security/certificate to encoding.
diff --git a/ndn-cpp/security/certificate/oid.cpp b/ndn-cpp/encoding/oid.cpp
similarity index 95%
rename from ndn-cpp/security/certificate/oid.cpp
rename to ndn-cpp/encoding/oid.cpp
index b03d93e..236e420 100644
--- a/ndn-cpp/security/certificate/oid.cpp
+++ b/ndn-cpp/encoding/oid.cpp
@@ -8,7 +8,7 @@
 #include <stdlib.h>
 #include <sstream>
 
-#include <ndn-cpp/security/certificate/oid.hpp>
+#include <ndn-cpp/encoding/oid.hpp>
 
 using namespace std;