Add query subcommand (only is_muted supported so far)

src/libexec/saturnin-au

             "down"   \
             "flip"   \
             "mute"   \
+            "query is_muted" \
             "unmute"
 }
 
     amixer -q sset Master mute
 }
 
+do_query() {
+    #
+    # Query properties
+    #
+    local query="$1"
+    debug -v query
+    case "$query" in
+        is_muted) sound_is_muted; return $? ;;
+        *)        usage                     ;;
+    esac
+}
+
 do_up() {
     #
     # turn volume up
     down)   action=down;   shift ;;
     flip)   action=flip;   shift ;;
     mute)   action=mute;   shift ;;
+    query)  action=query;  shift ; break ;;
     unmute) action=unmute; shift ;;
     "")     break                ;;
     *)      usage                ;;
 debug -v action
 
 case $action in
-    up|down|flip|mute|unmute) do_$action ;;
-    *)                        usage      ;;
+    up|down|flip|mute|query|unmute) do_$action "$@" ;;
+    *)                              usage           ;;
 esac