security: Reorganizing source code to prepare for support of two version of NDN certificates

This commit also removes unused ndn_digestSha256 function and deprecates
crypto::sha256 in favor of crypto::computeSha256Digest in util/crypto.hpp.

Change-Id: I24ee50ff073a96b868633bdf2cfade412d3605f3
Refs: #3098
diff --git a/tests/unit-tests/security/pib-data-fixture.hpp b/tests/unit-tests/security/pib-data-fixture.hpp
index 2f43113..04db21d 100644
--- a/tests/unit-tests/security/pib-data-fixture.hpp
+++ b/tests/unit-tests/security/pib-data-fixture.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2013-2015 Regents of the University of California.
+ * Copyright (c) 2013-2016 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -22,7 +22,7 @@
 #ifndef NDN_TESTS_PIB_DATA_FIXTURE_HPP
 #define NDN_TESTS_PIB_DATA_FIXTURE_HPP
 
-#include "security/identity-certificate.hpp"
+#include "security/v1/identity-certificate.hpp"
 
 #include "boost-test.hpp"
 
@@ -43,19 +43,19 @@
   Name id2Key1Name;
   Name id2Key2Name;
 
-  PublicKey id1Key1;
-  PublicKey id1Key2;
-  PublicKey id2Key1;
-  PublicKey id2Key2;
+  v1::PublicKey id1Key1;
+  v1::PublicKey id1Key2;
+  v1::PublicKey id2Key1;
+  v1::PublicKey id2Key2;
 
-  IdentityCertificate id1Key1Cert1;
-  IdentityCertificate id1Key1Cert2;
-  IdentityCertificate id1Key2Cert1;
-  IdentityCertificate id1Key2Cert2;
-  IdentityCertificate id2Key1Cert1;
-  IdentityCertificate id2Key1Cert2;
-  IdentityCertificate id2Key2Cert1;
-  IdentityCertificate id2Key2Cert2;
+  v1::IdentityCertificate id1Key1Cert1;
+  v1::IdentityCertificate id1Key1Cert2;
+  v1::IdentityCertificate id1Key2Cert1;
+  v1::IdentityCertificate id1Key2Cert2;
+  v1::IdentityCertificate id2Key1Cert1;
+  v1::IdentityCertificate id2Key1Cert2;
+  v1::IdentityCertificate id2Key2Cert1;
+  v1::IdentityCertificate id2Key2Cert2;
 };
 
 } // namespace security