#43 allow DTR instead of RTS

[William Welch]

It would be great if RMIR could optionally make use of DTR instead of RTS. I have FTDI cables for Arduino projects that would be handy to use for JP1.3 as well, but ( for reasons I don't know), the Arduino developers switched from RTS to DTR a couple of years ago, and so my adapters have DTR instead of RTS.

I was able to work around this by hand-soldering an extra wire for RTS, but the FTDI chip has fine-pitched pins.

I think the JP1 software for the IR Widget (IRScope) supports either RTS or DTR. thank you.