This change allows specification of the idle level and TX carrier output
level (through changed initialisation API), and more flexible specification
of pulses for write_pulses.
This is a breaking change for the esp32.RMT constructor API. Previous code
of this form:
esp32.RMT(..., carrier_duty_percent=D, carrier_freq=F)
will now raise an exception and should be changed to:
esp32.RMT(..., tx_carrier=(F, D, 1))
18e48a71ee