differentiate receiving and publishing mqtt for the new json option in user_config.h

#318 so as to avoid user with non modified controllers to have regression on receiving (per default receiving is activated for both json and simple and prioritary analysed for json)

ZgatewayRF315.ino

@@ -77,7 +77,7 @@ boolean RF315toMQTT(){
   }
 }
 
-#ifdef simplePublishing
+#ifdef simpleReceiving
   void MQTTtoRF315(char * topicOri, char * datacallback) {
   
     unsigned long data = strtoul(datacallback, NULL, 10); // we will not be able to pass values > 4294967295
@@ -133,7 +133,7 @@ boolean RF315toMQTT(){
   }
 #endif
 
-#ifdef jsonPublishing
+#ifdef jsonReceiving
   void MQTTtoRF315(char * topicOri, JsonObject& RF315data) { // json object decoding
   
    if (strcmp(topicOri,subjectMQTTtoRF315) == 0){