Added cmd MQTT sublevel and refactored function

mqtt.lua

@@ -2,14 +2,7 @@
 m=nil
 mqttConnected = false
 
--- MQTT extension
-function registerMqtt()
-    m = mqtt.Client("wordclock", 120)
-    -- on publish message receive event
-    m:on("message", function(client, topic, data)
-      print(topic .. ":" )
-      if data ~= nil then
-        print(data)
+function handleSingleCommand(client, topic, data)
     if (data == "ON") then
       briPercent=100
       m:publish(mqttPrefix .. "/clock", "ON", 0, 0)
@@ -33,6 +26,18 @@ function registerMqtt()
         print "Unknown MQTT command"
       end
     end
+
+end
+
+-- MQTT extension
+function registerMqtt()
+    m = mqtt.Client("wordclock", 120)
+    -- on publish message receive event
+    m:on("message", function(client, topic, data)
+      print(topic .. ":" )
+      if data ~= nil then
+        print(data)
+        handleSingleCommand(client, topic, data)
       end
     end)
     
@@ -44,6 +49,7 @@ function registerMqtt()
       tmr.alarm(3, 500, 0, function() 
 	      -- publish a message with data = hello, QoS = 0, retain = 0
 	      client:publish(mqttPrefix .. "/ip", tostring(wifi.sta.getip()), 0, 0)
+          client:subscribe(mqttPrefix .. "/cmd/#", 0)
       end)
     end,
     function(client, reason)