* add support for nexus protocol to RCSwitch library
Nexus protocol is used by temperature and humidity sensor that operate at 433 MHz.
It is used by various brands.
* calc separation limit for RCSwitch library automatically
Adding protocol for DOOYA 2700AC remote (used with DT82TV curtain motors)
This remote uses 40-bit code
PR #17139 is needed to support it in decimal format of RfSend command (JSON format works as is)
