Move validation-request.hpp to public API.  Moved static verifySha256WithRsaSignature to new Sha256WithRsaHandler::verify.
diff --git a/include/Makefile.am b/include/Makefile.am
index abe0340..b38a6d4 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -20,6 +20,7 @@
   $(wildcard ndn-cpp/security/encryption/*.*) \
   $(wildcard ndn-cpp/security/identity/*.*) \
   $(wildcard ndn-cpp/security/policy/*.*) \
+  $(wildcard ndn-cpp/security/signature/*.*) \
   $(wildcard ndn-cpp/transport/*.*) \
   $(wildcard ndn-cpp/util/*.*)