Added initial Melody Playback Ability

Now, controlled via MQTT a Playback of a melody can Start, Stop, Pause 
etc. 

Settings like speed, total duration, pauses etc can be set.

build/sketch/MQTT.hpp

@@ -0,0 +1,89 @@
+#line 1 "C:\\Users\\espi_\\Documents\\Arduino\\vesper\\MQTT.hpp"
+#pragma once
+
+const IPAddress MQTT_HOST(10,98,20,10);
+const int MQTT_PORT = 1883;
+
+AsyncMqttClient mqttClient;
+
+extern bool forceStop;
+extern volatile bool playing;
+
+String GetPayloadContent(char * data, size_t len) {
+	String content = "";
+	for(size_t i = 0; i < len; i++)
+	{
+		content.concat(data[i]);
+	}
+	return content;
+}
+
+void SuscribeMqtt() {
+
+	String topicPlayback = String("vesper/") + DEV_ID + "/control/playback";
+    String topicSetMelody = String("vesper/") + DEV_ID + "/control/setMelody";
+    String topicAddMelody = String("vesper/") + DEV_ID + "/control/add_melody";
+	
+    uint16_t control_id = mqttClient.subscribe(topicPlayback.c_str(), 2);
+    Serial.print("Subscribing to Playback Control topic, QoS 2, packetId: ");
+    Serial.println(control_id);
+
+	uint16_t set_melody_id = mqttClient.subscribe(topic_eBrake.c_str(), 2);
+    Serial.print("Subscribing to Set-Melody topic, QoS 2, packetId: ");
+    Serial.println(set_melody_id);
+
+	// doesn't work yet: 
+    uint16_t add_melody_id = mqttClient.subscribe(topicAddMelody.c_str(), 2);
+    Serial.print("Subscribing to Add-Melody topic, QoS 2, packetId: ");
+    Serial.println(add_melody_id);
+	
+}
+
+void PublishMqtt(unsigned long data) {
+	
+	//Doesn't publish anything yet.
+	String topicData = String("vesper/") + DEV_ID + "/data";
+	String payload = String(data);
+	mqttClient.publish(topicData.c_str(), 0, true, (char*)payload.c_str());
+
+}
+
+void OnMqttReceived(char * topic, char * payload, AsyncMqttClientMessageProperties properties, size_t len, size_t index, size_t total)
+{
+	
+	String topicPlayback = String("vesper/") + DEV_ID + "/control/playback";
+    String topicSetMelody = String("vesper/") + DEV_ID + "/control/setMelody";
+    String topicAddMelody = String("vesper/") + DEV_ID + "/control/add_melody";
+	
+	
+	String payloadContent = String(payload).substring(0, len);
+	
+	if (String(topic) == topicPlayback){		
+		if (len == 1 && payload[0] == '0') {  // Checking for raw '0' byte
+            forceStop = true;
+            Serial.println("STOPPING Playback!");
+        }
+		else if (len == 1 && payload[0] == '1'){
+			playing = true;
+		}
+	}
+	
+	else if (String(topic) == topicSetMelody) {
+		// Handle the playback command
+		handleJSON(payload);
+	}
+
+	else if (String(topic) == topicAddMelody) {
+		// Handle adding melody
+		Serial.println("Adding melody...");
+		// You can call a function here to handle adding the melody
+	}
+	else {
+		// Handle unknown topics
+		Serial.println("Unknown topic received.");
+	}
+}
+
+
+
+