checkcerts.sh: remove unnecessary `echo`s
 * NetDB: Add more su3 checks
 * SU3File: Improve CLI help
merge of 'a88d14e53014d9ab4a5d6e156e3abe2e496284c2'
     and 'bcf2bb5bf040195d80e26c4bf643ba0df8386f8a'