Mqtt discovery for ha (#323)

* MQTT discovery factoring

* add DHT discovery

* BME topic macro change

* add sensors to ha discovery

* correct a comment typo #327

* let the possibility at buildtime to don't publish service data

* reduce string usage

* change MQTT ONOFF actuator to ON OFF commands instead of true false

* add ZactuatorONOFF discovery

* add simple publishing for GPIO input

* Add RF switch and gateway discovery

.travis.yml

@@ -29,7 +29,7 @@ install:
   - python get.py
   - cd /usr/local/share/arduino/OpenMQTTGateway
   - arduino --pref "boardsmanager.additional.urls=http://arduino.esp8266.com/stable/package_esp8266com_index.json" --save-prefs
-  - arduino --install-boards esp8266:esp8266
+  - arduino --install-boards esp8266:esp8266:2.4.2
   - arduino --board $BD --save-prefs
 script:
   - arduino --verify --board $BD $PWD/OpenMQTTGateway.ino