Support topic tags in UI::CLI#debug and #warn

If the first argument passed to #debug or #warn is a Symbol, then it
is used to decide whether to print the message or not, basing on
--debug-* CLI options.

lib/iev/termbase/cli/ui.rb

@@ -45,10 +45,13 @@ def clear_progress
             $TERMBASE_PROGRESS ? "\r#{" " * 40}\r" : ""
           end
 
-          def cli_out(_level, *args)
+          def cli_out(level, *args)
+            topic = Symbol === args[0] ? args.shift : nil
             message = args.map(&:to_s).join(" ").chomp
             ui_tag = Thread.current[:iev_ui_tag]
 
+            return unless should_out?(level, topic)
+
             print [
               clear_progress,
               ui_tag,
@@ -57,6 +60,10 @@ def cli_out(_level, *args)
               "\n",
             ].join
           end
+
+          def should_out?(level, topic)
+            topic.nil? || level == :warn || $TERMBASE_DEBUG[topic]
+          end
         end
       end
     end