Compatibility for NEC protocol is fixed

[tkomde]

This PR fix #40, #39, #65 and enhance one.

First of all, the IR protocol used primarily in the world is the NEC protocol. The code in this repository was also inferred to assume the NEC protocol from the code comments.

#40 is a sample issue, so I have adapted to the NEC protocol.
#39 may also be a sample issue, I added the value instead of 0 because the NEC protocol requires an trail.

examples/irremote_transmit.py

    header=[9000, 4500], one=[560, 1700], zero=[560, 1700], trail=560

At the same time, decoding was adapted to the NEC protocol. This is a destructive change, but if this is not done, the RX/TX will not be consistent.

adafruit_irremote.py

        if (space * 0.75) <= pulse_length <= (space * 1.25):
            pulses[i] = True
        elif (mark * 0.75) <= pulse_length <= (mark * 1.25):
            pulses[i] = False

#65 is simply a typing change.

adafruit_irremote.py

    :param List[int] header: The length of header in microseconds, the length should be even
    :param List[int] one: The length of a one in microseconds
    :param List[int] zero: The length of a zero in microseconds

And the following is enhancement. The header is now variable instead of 2 fixed. This is useful for protocols that require a leader mark in addition to the header (e.g., Hitachi remote controls).

adafruit_irremote.py

        durations = array.array(
            "H", [0] * (len(self.header) + bits_to_send * 2 + (0 if self.trail is None else 1))
        )
        
        for i, _ in enumerate(self.header):
            durations[i] = self.header[i]

Please review and merge.
Because of the disruptive changes, a major version update would be desirable.

[FoamyGuy]

The explanation here and in the referenced issues along with the code changes make sense and look good to me. I did not test on hardware.

Thank you for these fixes and improvements @tkomde

[tkomde]

@FoamyGuy Thanks for your review and merge. I think it is safe to close issues #39 and #65.