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

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

ndns-dig
        1) enhance output option

find a bug that validator throws exception when getting a NDNS-NACK
refs: http://redmine.named-data.net/issues/2212

Change-Id: Ib06981c224ccad2a122a4505c84a60977184a55b
mgmt: management tools

refs #2034

Change-Id: I43ff11e0aa7e67f6207e75f139b7417779590efc
tools: management tools

refs #2034

Change-Id: Ib110e2d0e1214c3e95408a7f4d4679395e519319
tools: add ndns-demo

Change-Id: I250d7bf8a02ffec8aee3226bbf830bc3e9bbfa3f
tools: add NdnsShot

Change-Id: Ia34e0228e6e9164239f3412e5c419f965e35daec
add shell script to simplify testing

Change-Id: I15171cf06f3b9b3e55909109a3bf99d2d6176a35
set root zone at h243