improved saving settings of display #747, #746
disabled contrast for Nokia display #746
added Prometheus as compile option #719, #615
update MQTT lib to v1.4.1
limit decimal places to 2 in `live`
added `-DPIO_FRAMEWORK_ARDUINO_MMU_CACHE16_IRAM48` to esp8266 debug build #657
a `max-module-power` of `0` disables channel in live view `setup`