- provide a queue for the outgoing messages, don't depend on the MQTT
callback implementation details and always postpone the actual transfer.
- generate user input parsers using re2c, adds special PlatformIO build handlers
- add terminal command to show GPIO info and send a simple payload
- rework button<->action presets into value<->terminal command presets and custom ones
through the use of `irCmd<VALUE>` settings, where the VALUE is taken from the simple payload
(yet, it does not understand repeated codes, but that's something to add later *or* use rpnlib)
- add tx message integration for the relay module via `irRelayOn#` and `irRelayOff#`
- rework simple payload to include 'repeats' value for the 'IRsend::send()'
also adds internal 'series', 'delay' and includes full 64bit 'value'
(as uppercase HEX, instead of decimal)
- rework raw payload to use 'series' instead of 'repeats', and provide a
clear distinction between the usec time and the options of the message
by moving the required options to the front and separating them using ':'
(just like the simple variant)
- make RX and TX pin a runtime setting, make RX and TX support a build flag
- small test framework to check whether internal string encode<->decode works
Also updates the hexEncode & hexDecode implementations to use
'iterators' instead of just pointer + index.
