This will add support for the KingArt Wifi Curtain Switch. There are no buttons in the web interface as I could not figure out how to create them (any help on that is welcome).

For now the switch can be controlled over MQTT:
"{hostname}/curtain/set"
"{hostname}/curtain"

* rfm69: fix types of settings

* down

* RPN rules (WIP)

* RPN rules web interface, MQTT inputs

* Stickyness, rpn.ops,...

* Perform light updates only when value changes

* Improve wsSend performance

* Revert PR test

* Check TERMINAL_SUPPORT for _rpnInitCommands and remove unused variable

* Fix merge

* formatting

* disable by default (?)

* changelog

* comment

* remove debug function wrappers in favour of var activation

* fixup! comment

* travis: move build flags tests outside of hardware header

* mqtt: fix typo

* travis: use files instead of bundling test cases into script

* fixup! travis: use files instead of bundling test cases into script

* fix variable expansion, remove custom h at the end

* add ade7953 to sensors list

* custom.h path as variable

* shellcheck

* fix printf syntax, silent again

* fix bash 4.3 treating empty array as unset variable