5.1.6 20170606
* Shrink code
* Removed online configuration of Domoticz In and Domoticz Out MQTT
strings
* Removed commands DomoticzInTopic and DomoticzOutTopic
* Add define KEY_HOLD_TIME to configure button hold threshold before
sending MQTT Hold message
* Add command StateText4 to configure button MQTT Hold text (=
MQTT_CMND_HOLD)
* Add command SetOption11 0|1 to swap pushbutton single and double press
functionality (#200)
* Add command SwitchMode<x> 5 (PUSHBUTTONHOLD) and 6
(PUSHBUTTONHOLD_INV) (#489)