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/src/clients/iterative-query-controller.cpp b/src/clients/iterative-query-controller.cpp
index 1d7af26..c5e5104 100644
--- a/src/clients/iterative-query-controller.cpp
+++ b/src/clients/iterative-query-controller.cpp
@@ -74,10 +74,7 @@
   switch (m_step) {
   case QUERY_STEP_QUERY_NS:
     if (ndnsType == NDNS_NACK) {
-      if (m_nFinishedComps + m_nTryComps == m_dstLabel.size() && m_rrType != label::NS_RR_TYPE)
-        m_step = QUERY_STEP_QUERY_RR;
-      else
-        m_step = QUERY_STEP_ANSWER_STUB;
+      m_step = QUERY_STEP_QUERY_RR;
     }
     else if (ndnsType == NDNS_RESP) {
       if (m_nFinishedComps + m_nTryComps == m_dstLabel.size() && m_rrType == label::NS_RR_TYPE) {