tools: improve user experience by choosing best certificate
automatically and print final response in a pretty way

ndns-update
 - pick the best certificate to sign the Update automatically
 - support multiple token for content option

ndns-dig
 - enhance output option
 - change behavior of iterative query controller when NS query is NACKed

logger
 - set default logger output to std::cerr

Change-Id: Ib06981c224ccad2a122a4505c84a60977184a55b
diff --git a/tools/ndns-daemon.cpp b/tools/ndns-daemon.cpp
index 5937562..b40f6f0 100644
--- a/tools/ndns-daemon.cpp
+++ b/tools/ndns-daemon.cpp
@@ -218,11 +218,12 @@
     // NFD does not to forward Interests to the face it was received from.
     // If the name server and its validator share same face,
     // the validator cannot be forwarded to the name server itself
+    // For current, two faces are used here.
+
     // refs: http://redmine.named-data.net/issues/2206
     // @TODO enhance validator to get the certificate from the local db if it has
 
     NdnsDaemon daemon(configFile, face, validatorFace);
-
     face.processEvents();
   }
   catch (std::exception& e) {