related to #52 (#59)

* Added OTA-Support for ESP8266

#52 thanks!

OpenMQTTGateway.ino

@@ -56,6 +56,9 @@ void callback(char*topic, byte* payload,unsigned int length);
 
 #ifdef ESP8266
   #include <ESP8266WiFi.h>
+  #include <ESP8266mDNS.h>
+  #include <WiFiUdp.h>
+  #include <ArduinoOTA.h>
   WiFiClient eClient;
 #else
   #include <Ethernet.h>
@@ -121,6 +124,33 @@ void setup()
   #ifdef ESP8266
     //Begining wifi connection in case of ESP8266
     setup_wifi();
+    // Port defaults to 8266
+    ArduinoOTA.setPort(ota_port);
+
+    // Hostname defaults to esp8266-[ChipID]
+    ArduinoOTA.setHostname(ota_hostname);
+
+    // No authentication by default
+    ArduinoOTA.setPassword(ota_password);
+
+    ArduinoOTA.onStart([]() {
+      Serial.println("Start");
+    });
+    ArduinoOTA.onEnd([]() {
+      Serial.println("\nEnd");
+    });
+    ArduinoOTA.onProgress([](unsigned int progress, unsigned int total) {
+      Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
+    });
+    ArduinoOTA.onError([](ota_error_t error) {
+      Serial.printf("Error[%u]: ", error);
+      if (error == OTA_AUTH_ERROR) Serial.println("Auth Failed");
+      else if (error == OTA_BEGIN_ERROR) Serial.println("Begin Failed");
+      else if (error == OTA_CONNECT_ERROR) Serial.println("Connect Failed");
+      else if (error == OTA_RECEIVE_ERROR) Serial.println("Receive Failed");
+      else if (error == OTA_END_ERROR) Serial.println("End Failed");
+    });
+    ArduinoOTA.begin();
   #else
     //Begining ethernet connection in case of Arduino + W5100
     setup_ethernet();
@@ -189,6 +219,9 @@ void loop()
   } else { //connected
     // MQTT loop
     client.loop();
+    #ifdef ESP8266
+      ArduinoOTA.handle();
+    #endif
     
     #ifdef ZsensorDHT
       MeasureTempAndHum(); //Addon to measure the temperature with a DHT